SSS7.8

    Iron nanoparticles are capable of removing heavy metals due to their significant specific surface relative to their weight. Iron nano powders with an average particle size of 50 nm and very high reactivity are suitable for groundwater purification and industrial wastewater treatment. In fact, the very high ability of iron nanoparticles of zero valences in its reduction and high reactivity makes this material a good choice in achieving the above goals. Due to its small size, after injection, these particles can be spaced and transferred easily. On the other hand, natural zeolites are important aluminosilicates in adsorption processes due to their low cost. In this research activity, a comparison was made between the adsorption percentage of zero iron nanoparticles as an industrial adsorbent with the minerals, calcite, and zeolite. By adding 1 gram of adsorbent powder to a solution of 10 ppm cadmium, decreased cadmium concentrations at different time intervals in three experiments with two replications was measured by an atomic absorption spectrometer. The results showed that 38.4% of cadmium was adsorbed by nanoparticles after 3 hours, which was 8.53% and 5.5%, respectively for the usage of calcite and zeolite mineral adsorbents. This indicates an increase of 29.86 and 32.9% in adsorption of nanoparticle adsorbent compared to calcite and zeolite. To investigate the effect of adsorption percentage in a saturated porous medium, 100 ml of 10 ppm cadmium solution in the presence of 50 g of soil with an average diameter of 1.11 mm saturated with 50 ml of cadmium solution with the same concentration in reaction with 1 g of adsorbent powder was used 22 hours after the start of the experiment, 51.55% of the total cadmium was removed from the environment by soil and industrial adsorbent, and the adsorption percentages for calcite and zeolite in the porous medium were 17.5% and 7.75%, respectively.

Keywords: Cadmium, Zero iron nanoparticles, Calcite, Zeolite.

How to cite: Sotoodeh Nia, S., Taheri, S. M., Mahdavi Mazdeh, A., and Wohnlich, S.: Reduction of cadmium contaminated groundwater pollution by using mineral adsorbents and industrial sorbents  , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-614, https://doi.org/10.5194/egusphere-egu21-614, 2021.

The use of environmentally friendly low-cost sorbents such as biochar and wood-based activated carbon as soil amendment has shown promising results in immobilizing organic and inorganic contaminants. They can be suitable soil remediation options at sites with residual contamination, where the contaminated hotspot has been removed. The effectiveness of biochar and activated carbon application is site dependent. Specifically, dissolved organic carbon (DOC), pH, and ionic strength in the pore water are important factors which can influence the extent of contaminant immobilization. Although there has been significant progress in developing alternative carbonaceous sorbents, the efficiency of these materials in a diverse range of soil and pore water conditions remains an open question. To address this knowledge gap, the present study investigates the influence of pore water chemistry on sorption of organic and inorganic contaminants to biochar and wood-based activated carbon. Sorption of selected non-polar, polar and ionizable polycyclic aromatic compounds (PACs) and inorganic Cadmium (Cd) to biochar and a wood-based activated carbon was studied under different pore water chemistry conditions. Batch sorption experiments were conducted using an experimental design approach (Box Behnken Design) with three different levels of DOC, pH, and ionic strength, yielding background solutions mimicking a wide spectrum of pore water chemistries. Sorption K_D values [L/kg] were calculated from aqueous contaminant concentrations after equilibration. Results were analyzed using a response surface methodology (RSM) approach on Minitab 19 and fitted to a model equation using linear, squared and two-way interactions terms.

Our results show that the ionizable PAC (phenyl phenol) and Cd were most affected by changes in pore water chemistries. For phenyl phenol, the presence of a phenolic group can cause H-bonding and electrostatic attraction and repulsion, while pH-dependent changes in speciation, precipitation and electrostatic attraction can occur for Cd. Sorption of all PACs negatively correlated with DOC, indicating competition of DOC with PACs for sorption sites. Sorption of non-polar (acenaphthene), polar N substituted (carbazole) and ionizable (phenyl phenol) PACs was hindered under acidic conditions, due to precipitation of DOC. For Cd, higher pH and low DOC levels favored sorption. This can be attributed to a lower Cd solubility in the presence of leached phosphate at higher pH, and a predominance of Cd(OH)₂ in the neutral to alkaline regime. Our findings highlight the importance of considering a combination of site- and contaminant-specific factors when planning to apply carbonaceous sorbents for contaminant immobilization, with pH and DOC generally being more important than ionic strength.

How to cite: Chaudhuri, S., Sigmund, G., von Rautenkranz, H., Hueffer, T., and Hofmann, T.: Importance of site-specific factors for the immobilization of contaminants using biochar and wood-based activated carbon, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2259, https://doi.org/10.5194/egusphere-egu21-2259, 2021.

The objective of this paper was to investigate the molecular characterization of individual humic substances ( fulvic acids-FAs, humic ascids-HAs, and humins-HNs), which are the most reactive soil components and exhibit high sorption capacity in relation to various groups of organic contaminants. A wide spectrum of spectroscopic (UV-VIS, VIS-nearIR), as well as electrochemical (zeta potential, particle size diameter, polidyspersity index), methods were applied to find the relevant differences in the behavior, formation, composition and sorption properties of HS fractions derived from various mineral soils.

Soil material (n = 30) used for the study were sampled from the surface layer (0–30 cm) of agricultural soils. FAs and HAs were isolated by sequential extraction in alkaline and acidic solutions, according to the International Humic Substances Society method, while HNs was determined in the soil residue (after FAs and HAs extraction) by mineral fraction digestion using a 0.1M HCL/0.3M HF mixture and DMSO.

Our study showed that significant differences in the molecular structures of FAs, HAs and HNs occurred. Optical analysis confirmed the lower molecular weight of FAs with high amount of lignin-like compounds and the higher weighted aliphatic–aromatic structure of HAs. The HNs were characterized by a very pronounced and strong condensed structure associated with the highest molecular weight. HAs and HNs molecules exhibited an abundance of acidic, phenolic and amine functional groups at the aromatic ring and aliphatic chains, while FAs mainly showed the presence of methyl, methylene, ethenyl and carboxyl reactive groups. HS was characterized by high polydispersity related with their structure. FAs were characterized by ellipsoidal shape as being associated to the long aliphatic chains, while HAs and HNs revealed a smaller particle diameter and a more spherical shape caused by the higher intermolecular forcing between the particles.  

The observed trends directly indicate that individual HS fractions differ in behavior, formation, composition and sorption properties, which reflects their binding potential to different group of organic contaminants, but the general properties of individual fractions are similar and do not depend on the type of soil.

Acknowledgement: The studies were supported from the National Science Centre project No. 2018/29/N/ST10/01320 “Analysis of the fractional composition and sorption properties of humic substances in relation to various groups of organic contaminants”

How to cite: Ukalska-Jaruga, A., Bejger, R., Debaene, G., and Smreczak, B.: Structural characterization of soil organic matter individual fractions (fulvic acids, humic acids and humins) in relation to potential sorption of organic contaminants, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4125, https://doi.org/10.5194/egusphere-egu21-4125, 2021.

The distribution of V chemical species in natural waters has been scarcely studied mainly due to its high reactivity and wide variety of co-existing forms depending on number of factors including metal concentration, pH, Eh, ionic strength, the presence of complexing ligands etc. ¹ Importance of V speciation studies lies in the dependence of toxicity and bioavailability upon different chemical species that V takes form of in natural waters, with V(V) being most toxic and soluble ⁴. Although thermodynamic calculations predict V(V) as dominant species in well oxidized marine environments, V(IV) is also reported to be present due to its ability to form stable complexes with Dissolved Organic Matter (DOM) related ligands found in natural waters ^2–6. Furthermore, previous research report that Humic Acid (HA) acts as an adsorbent and complexing agent for many trace metals (Cu²⁺, Zn²⁺, Cd²⁺, Fe²⁺). However, HA impact on V speciation and potential removal from the water column of natural aquatic systems is still unclear ⁷.

Interaction of V(V) with HA was investigated in model solutions under different conditions using anion-exchange based Ion Chromatography with UV/Vis detection system. The goal of the research was to mimic natural conditions, as experimentally possible, in order to assess likely contribution of HA to changes in V speciation and potential removal from the solution by adsorption on HA colloids. Temporal study on V(V) reduction kinetics was conducted using strong chelator (EDTA) which was added in the filtrated solution prior to measurement in order to stabilize distribution of V species in the model solutions. Removal of V(V) from the solution on HA particles was quantified using calibration curves. Desorption experiments were performed with the addition of EDTA in un-filtrated solutions 24 hours before measurement.

Research showed that V interaction with HA is highly dependant on ionic strength of solution as well as ratios between V(V) and HA present in the solution. Desorption experiments showed almost complete recovery of V in the solutions with higher ionic strength, mainly in the form of V(IV). Observed reduction and removal of V(V) from the solution on the pH of natural waters suggest high impact of DOM on V speciation and consequently its toxicity and bioavailability.  

References:

1           P. N. Linnik and R. P. Linnik, Russ. J. Gen. Chem., 2018, 88, 2997–3007.

2           J. P. Gustafsson, Appl. Geochemistry, 2019, 102, 1–25.

3           P. Bernárdez, N. Ospina-Alvarez, M. Caetano and R. Prego, Environ. Chem., 2013, 10, 42–53.

4           D. Wang and S. A. Sañudo Wilhelmy, Mar. Chem., 2009, 117, 52–58.

5           K. Hirayama, S. Kageyama and N. Unohara, Analyst, 1992, 117, 13–17.

6           D. Wang and S. A. Sañudo-Wilhelmy, Mar. Chem., 2008, 112, 72–80.

7           Y. Yu, M. Liu and J. Yang, Chem. Ecol., 2018, 34, 548–564.

How to cite: Knežević, L. and Bura-Nakić, E.: Investigation of V(V) interaction with Humic Acid in aqueous solution using anion-exchange Ion Chromatography, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4460, https://doi.org/10.5194/egusphere-egu21-4460, 2021.

Pollution of marine environment by antibiotics and/or heavy metals is a serious global issue. Remediation of polluted marine environments is urgently needed for achieving the United Nations Sustainable Development Goals (SDGs) to end poverty and protect the planet from degradation. Biochar, as an environmentally friendly material, has been widely used as adsorbents to remediate contaminated soil or fresh water. However, application of biochar in remediation of marine environment is poorly understood. Therefore, a batch of biochars produced from pyrolysis of two marine algae residues, Enteromorpha (Enteromorpha prolifera) and blended seaweed wastes, at 300–700 °C was used to investigate their performance in sulfamethoxazole (SMX) sorption in seawater. Additionally, a modified biochar (MBC) was prepared by pyrolyzing AlCl₃ pretreated sawdust to improve their performance in remediating a marine sediment contaminated with heavy metals and antibiotics using two mesocosmic experiments. The results showed the algae-derived biochars had relatively low C content, but high contents of O- and S-containing functional groups and crystalline minerals associated with S, Ca, K, and Mg. The maximum adsorption capacity of these algae-derived biochars to SMX was 4880 mg kg^-1, equivalent to a commercial coconut shell derived activated carbon. Potential mechanisms responsible for the SMX sorption mainly included pore-filling, cation bridging, negative charge-assisted H-bond [(–)CAHB], and π-π EDA interaction. The surface of MBC was rough with layered homogeneous sheets, and the nano-scale Al minerals formed on the C matrix. Moreover, its settling properties and adsorption capacities to Cu, Cd, SMX, and tetracycline (TC) were highly improved relative to the unmodified sawdust derived biochar (SBC). As a result, addition of MBC at 4% (w/w) performed  better in improving the survival rate and condition index of the clams in the contaminated sediments than SBC. Furthermore, MBC application decreased bioaccumulation of Cu and Cd in the clams. Both SBC and MBC increased the microbial abundance and diversity in the contaminated sediments, and MBC decreased the abundance of Cu resistant bacteria (e.g., Firmicute and Gemmatimonadetes). For the sediment contaminated by antibiotics, lower content of SMX and TC in the overlying water and pore water was observed in the sediment amended with MBC than SBC, leading to the reduction of total antibiotic resistance genes. Therefore, these findings show the potential of functional/modified biochar to remediate marine sediments contaminated with heavy metals and antibiotics.

How to cite: Zheng, H., Ma, X., Zhao, M., Zhang, C., and Xing, B.: Remediation of antibiotic and heavy metal pollution in marine environment, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4959, https://doi.org/10.5194/egusphere-egu21-4959, 2021.

Oxidation  of sulfamethoxazole by biochar-activated persulfate: Influence of the preparation temperature on the activity of biochar from spent coffee grounds

Spiros Giannakopoulos¹, Zacharias Frontistis²  John Vakros¹, Ioannis D. Manariotis³, Dionissios Mantzavinos¹

¹Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504 Patras, Greece

² Department of Chemical Engineering, University of Western Macedonia, GR–50100, Kozani, Greece

³Department of Civil Engineering, Environmental Engineering Laboratory, University of Patras, University Campus, GR-26504 Patras, Greece

ABSTRACT

Biochar is a carbonaceous material prepared by pyrolysis of raw biomass. Due ti its unique physicochemical properties biochar can be used in several processes. In this study biochar from spent coffee grounds was produced under different pyrolysis temperatures and used as persulfate activator for the oxidation of sulfamethoxazole.

Specifically, biochar from spent coffee grounds was synthesized under five different pyrolysis temperatures −300, 400, 600, 700, and 850°C  for 1 h, and employed as catalyst for the removal of sulfamethoxazole (SMX) by persulfate activation. SMX degradation experiments were performed mainly in ultra-pure water (UPW) with a biochar (catalyst ) concentration of 100 mg /L, a persulfate concentration of 500 mg/L and a substance concentration of 500 μg/L and in pH at different pH values (3 <pH <10). Real matrices, besides UPW, were also tested, namely treated wastewater (WW) and bottled water (BW), while synthetic solutions were prepared spiking UPW with bicarbonate, chloride, humic acid or alcohols.

Τhe presence of the biochar is important for the process as it contributes to the activation of the SPS resulting in faster and greater removal of the substance. The rate of adsorption and oxidation, which follows a pseudo-order kinetic model, increases when biochar, produced at  higher pyrolysis temperature, is used for the experiment. The maximum removal is observed in case of the highest pyrolysis temperature (T= 850 °C) biochar.

The presence of an acidic environment generally facilitates the adsorption of the micro-pollutant compared to the alkaline environment while the oxidation reaction is slowed down when a real aqueous matrix is used. The addition of alcohol has a small effect on reducing the efficiency of the process, which may indicate that the reaction pathway is under electron transfer control instead of active radicals.

The research work was supported by the Hellenic Foundation for Research and Innovation (H.F.R.I.) under the “First Call for H.F.R.I. Research Projects to support Faculty members and Researchers and the procurement of high-cost research equipment grant” (Project Number: 81080).

How to cite: Giannakopoulos, S., Frontistis, Z., Vakros, J., D. Manariotis, I., and Mantzavinos, D.: Oxidation  of sulfamethoxazole by biochar-activated persulfate: Influence of the preparation temperature on the activity of biochar from spent coffee grounds, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-5035, https://doi.org/10.5194/egusphere-egu21-5035, 2021.

Amendment of alluvial sediments with carbon rich materials such as biochars can be an effective method for controlling the penetration of hazardous substances from river water into drinking water sources during river bank filtration (RBF). In this work, the transport of chlorinated phenols (CPs) during simulated RBF through Danube alluvial sediment with and without biochar amendment was studied. In order to assess the effect of the biochar amendment on CPs retention in the alluvial sediment, column experiments were carried out, with the addition of biocide to exclude the influence of biodegradation. Four CPs that differ in polarity were used as sorbates: 4-chlorophenol (4-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP) and pentachlorophenol (PCP). For the column packing, Danube alluvial sediment was used, characterized as a mesoporous sandy material with low organic carbon content (1.57 %) and small specific surface area (1.65 m²/g). In contrast, the material used as the amendment in the column experiment is a biochar with high organic carbon content (89.8 %) and large specific surface area (341 m²/g). The breakthrough curves obtained for the alluvial sediment column without biochar amendment showed poor retention of all investigated CPs. Retardation factors (R_d) for 4-CP, 2,4-DCP and 2,4,6-TCP were 1.65, 1.98 and 1.48, respectively, whereas for PCP, R_d was somewhat higher (4.28) most likely due to the fact that it’s nonpolar nature greatly affects its distribution between the solid and aqueous phase. The addition of biochar into the alluvial sediment at a 0.5 % mass ratio significantly increased the retardation of all investigated CPs. The obtained R_d values for 4-CP, 2,4-DCP, 2,4,6-TCP and PCP were 102, 83, 78 and 92, respectively. The general increase in retardation of all investigated CPs can be explained by the increase of organic carbon content in the alluvial sediment by the addition of biochar, which is known to be the main fraction for organic components sorption in sediments and soils. In addition, the enhanced affinity of the alluvial sediment to retain the more polar CPs after biochar amendment indicates that sorption is carried out not only through nonpolar interactions, but also by electrostatic interactions between the CPs and functional groups on the surface of the biochar. The results show that biochar amendment of alluvial sediments could have a great potential for organic contaminants retention in the RBF zone, thus decreasing the risk of groundwater and drinking water sources contamination.

Acknowledgement: The authors acknowledge financial support of the Ministry of Education, Science and Technological Development of the Republic of Serbia (Grant No. ‪451-03-68/‪2020-14/ 200125). The authors want to express their gratitude to Basna d.o.o. Čačak for providing the biochar.

How to cite: Apostolović, T., Tričković, J., Kragulj Isakovski, M., Maletić, S., Zeremski, T., Dubovina, M., and Agbaba, J.: The effect of biochar amendment on chlorinated phenols retention in alluvial sediments during river bank filtration, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-6782, https://doi.org/10.5194/egusphere-egu21-6782, 2021.

Mitrovica area (northern Kosovo) presents contamination by PTE in agricultural soils caused by smelter emissions and their transfer and accumulation in cultivated plants. Soil A and B, sampled from two sites in Mitrovica municipality, showed a total content of Pb and Zn of 2153 and 3087 mg kg^-1, and 3214 and 4619 mg kg^-1. A pot experiment was performed to understand the phytoremediation potential of two non-food crops (Sorghum bicolor L. Moench and Brassica napus Westar), chosen for their economic importance and heavy metal accumulation capacities. Bioconcentration factor, translocation factor and tolerance Indexes clearly indicated a better performance of canola in tolerating Pb and Zn, especially in soil B, even if contained higher amounts of both metals. To evaluate different chemical and physical forms of Pb and Zn in the two soils, a modified BCR extraction scheme was employed to determine amounts bound to different soil components: exchangeable fraction (acid-soluble, carbonate and exchangeable bound), reducing fraction (metal bound to Fe- or Mn-oxides), oxidizable fraction (organic and sulphide bound), and residual fraction (strongest binding with crystalline structure). A comparison of the sum of Pb and Zn concentrations obtained from BCR relative to total digestion values (pseudo-total concentrations) showed recoveries close to 100%. Very small amounts of Pb were released during step 1 (exchangeable fraction) (6,86% - soil A and 2,12% - soil B). The highest concentration of Pb, 62,62% in soil A and 56,68% in soil B, decreased in the reducing fraction (step 2), probably occurring mainly as forms bound to Fe/Mn oxides. Step 3 (oxidizable-organic matter “OM” and sulphides) released amounts of 23,15% and 20,32% of total Pb in soil A and B. Residual fraction presented very different amounts of Pb (7,87% in soil A and 20,88% in soil B). Unlike Pb, no important differences were found in the distribution of Zn among the various fraction of the two soils, with the greater amounts contained in the exchangeable fraction of both soils, 31.11% in soil A and 21.92% in soil B. Very small amounts of Zn were released during step 2 (19,3% in soil A and 22,27% in soil B) whereas step 3 released the highest amounts of Zn in both soils (36,56% in A and 40,17% in B). Residual fraction presents similar amounts of total Zn, 13,03% in A e 15,64% in B, showing an opposite trend with respect to Pb. So, a major portion of total Pb was associated to the reducing fraction, while Zn was found mostly in oxidable one, indipendent on the origin of samples. Pb strongly interacts with Fe-/Mn oxides, and, in soil B, a greater amount is immobilized in the residual fraction. These results suggest lower mobility and bioavailability of Pb in soil B with respect to soil A, partially explaining the pot experiment.

How to cite: Miano, T., Mondelli, D., Piscitelli, L., Voca, H., and D'Orazio, V.: Bioavailability and geochemical forms of Pb and Zn in Kosovo contaminated soils, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7649, https://doi.org/10.5194/egusphere-egu21-7649, 2021.

Humin fraction of soil organic matter is assigned to play an important role in carbon sequestration and sorption of xenobiotics. This study concerns the properties of humin (elemental composition, FTIR and SEM-EDS of humin ash) isolated from mollic horizons of eight Chernozems and Phaeozems, used as arable soils in various regions of Poland. Isolation procedure was described by Weber et al. (2021) in another abstract presented in this session. Investigated soils differed in the content of TOC, ranging from 13.3 to 41.7 g kg⁻¹, as well as texture from loam (Magnice, Pyrzyce) through silt loam (Trzebnik, Ciepłowody, Hrubieszów) and sandy clay loam (Psary) till clay (Ziemnice, Kętrzyn). They also differed in their pH values (from 5.64 to 7.71), and CEC (from 21.6 to  53.2cmol(+)kg^-1). Ash content of humin varied between 22.89%  - 54.50%, which is typical for humin originated from mineral soils (Stevenson 1994). This parameter was not correlated neither with the content of <0.002 mm fraction nor TOC content. SEM-EDS analyzes revealed that ash contained mainly Mg (3 – 14 weight%), Al (4 – 22 weight %) and Ti (10 – 25 weight%), depending on the area studied. The lowest pH as well as  the highest TOC and CEC showed Trzebnik soil. Humin from this soil indicated the lowest content of carbon (30.84 %) and the highest values of H/C ratio, which point out to the higher aliphacity of their molecules (Rice and MacCarthy 1991). High O/C ratio (0.91) calculated for humin from Trzebnik is common for more oxidized carbohydrate molecules and makes them similar to fulvic acids which are polysaccharidic in nature (Tan 2014). In contrast, the lowest TOC and CEC were determined in Ciepłowody soil. Humin molecules from this soil indicated the highest carbon content (43.12 %) and the lowest H/C ratio, what reflects the highest aromacity among investigated samples. FTIR spectra confirmed results from elemental analysis and indicated that humin from Ciepłowody and Hrubieszów was the most aromatic among all analyzed soils.

References:

Hayes M.H.B., Mylotte R., Swift R.S. 2017. Humin: Its Composition and Importance in Soil Organic Matter. In: Sparks D.L. (ed) Advances in Agronomy, Vol. 143, Academic Press, Burlington, 47–138.

Rice J.A., MacCarthy P. 1991. Statistical evaluation of the elemental composition of humic substances. Org. Geochem, 17(5), 635-648.

Stevenson FJ. 1994. Humus chemistry: Genesis, composition, and reactions. New York: John Wiley and Sons, p 512.

Swift R.S. 1996. Organic matter characterization. In: Methods of soil analysis. Part 3. Chemical methods – SSSA Book Series no.5. Soil Science Society of America and American Society of Agronomy, pp 1011-1068.

Tan HK. 2014. Humic matter in soil and the environment, 2^nd edn. CRC Press, Boca Raton, p 463.

Weber J., Jamroz E., Kocowicz A., Debicka M., Ukalska-Jaruga A., Mielnik L., Bejger R., Jerzykiewicz M., Bekier J., Ćwieląg-Piasecka I. Recommendations for isolation of humin fraction from soil material. EGU21-8315

Acknowledgements

This work was supported by the National Science Center (NCN) Poland (project No 2018/31/B/ST10/00677 “Chemical and spectroscopic properties of soil humin fraction in relation to their mutual interaction with pesticides")

How to cite: Jamroz, E., Weber, J., Jerzykiewicz, M., Kocowicz, A., Dębicka, M., Bekier, J., Ćwieląg-Piasecka, I., Ukalska-Jaruga, A., Mielnik, L., and Bejger, R.: Selected properties of the humin fraction isolated from Chernozems and Phaeozems from various regions of Poland, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-8456, https://doi.org/10.5194/egusphere-egu21-8456, 2021.

Numerous factors affect adsorption phenomena in solid–liquid systems. Critical factors are the sorbent dose and initial concentrations of the contaminants in the system. However, the combination of these two factors and their effects on removal prediction are largely unexplored. In this study, batch experiments were conducted to examine such effects on the adsorption of 2-[4-(dimethylamino) styryl]-1-methylpyridinium iodide cationic dye (2-ASP) in contaminated water to humic acid coated magnetic nanoparticles (HA-MNPs). Dimensional analysis and Buckingham’s π theorem were subsequently used to assess the relationship between the sorbent dose, initial concentration, and percent removal. Results of dimensional analysis along with experimental data suggest that sorbent dose and sorbate concentration ratio are the main variables controlling sorption of dye on HA-MNPs. In conventional isothermal studies, the isotherm equations are developed based on experiments of one sorbent dose which cannot be generalized for all sorbent doses.  In this study, a power function (Isotherm-like) model was obtained from the dimensional analysis that can describe precisely the sorption process of dye on HA-MNPs as a function of equilibrium concentration and sorbent dose ratio. Moreover, a relation is deduced for prediction of removal percent as a function of sorbent dose and initial concentration ratio with R² of 0.98.

Keywords: Remediation, Dimensional analysis, Isotherm-like model, Magnetic nanoparticle, Styryl pyridinium dyes, Water treatment

How to cite: Esmaeilian, A. and O'Shea, K. E.: Application of dimensional analysis in removal prediction of 2-[4-(dimethylamino) styryl]-1-methylpyridinium iodide dye using humic acid coated magnetic nanoparticle, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9142, https://doi.org/10.5194/egusphere-egu21-9142, 2021.

Drinking water is a vital component for sustaining life on our planet. Unfortunately, the presence of numerous recalcitrant organic and inorganic contaminants in the aquatic environment cause adverse health effects in humans, rendering water consumption dangerous. Therefore, it has become urgent to develop and establish treatment methods to decontaminate waters from persistent chemicals. Adsorption is such a promising method, mainly due to its low-cost, high performance, easiness of operation, and effectiveness in a wide pH range. The current research work focuses on the effectiveness of a novel Zirconium-based metal organic framework (MOF) solvothermally synthesized in our laboratory to remove Indigo Carmine from water. Indigo Carmine is a water-soluble organic salt used as colorant in pharmaceuticals, foods, and cosmetics; however, its presence in water has been associated with hypertension, cardiovascular and respiratory effects, carcinogenesis, and neurotoxicity. MOFs are novel compounds consisting of metals ions coordinated to organic ligands. They possess high surface areas and porosity, which classify them as ideal for the adsorption of various water contaminants. This work aims to develop comprehensive insights that will lead to more advanced efficient adsorption processes.

How to cite: Kekes, T., Kolliopoulos, G., and Tzia, C.: Zirconium-based metal organic framework as novel adsorbent for Indigo Carmine, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9194, https://doi.org/10.5194/egusphere-egu21-9194, 2021.

The reactions of toxicants with organic substances of a humic nature are complex and depend on many geochemical factors. Differences in the mechanisms of the selected toxicants binding with organic natural substances of various natural waters - atmospheric precipitation, lake waters (acidic and alkaline), lysimetric waters are especially interesting. Due to significant concentration differences, features of functional groups and size distribution of components, the inactivation features of humic substances are selective and highly variable. We studied the waters of an acid lake near the city of Valday (Valday National Park, conditionally a background lake) and alkaline lake Valday (city of Valday, local technogenic influence). Near each lake there was a sediment collector (a container for collecting atmospheric precipitation) and a lysimeter (a container under the soil for collecting soil moisture) under the humus horizon (about 20 cm). Particular attention was paid to soil (lysimetric) waters with varying degrees of anthropogenic impact. We considered the behavior of a large group of heavy metals, as well as benzopyrene. To assess the composition and qualitative features of organic substances, gas chromatography-mass spectrometric methods of analysis were used. Chromatographic methods were used to assess the molecular weight distribution of the components. Possible reaction mechanisms were studied by IR spectral methods. Evaluation of the reactivity of organic substances was carried out by the methods of dynamic light scattering (zeta potential, MM, size) using the "Zeta-sizer nano". In addition to humic substances in the waters, the contents of autochthonous organic matter were estimated, especially in an alkaline lake, which in some periods prevailed over humic ones. In addition to humic substances in the waters, the contents of autochthonous organic matter were estimated, especially in an alkaline lake, which in some periods prevailed over humic ones. For separation, exchange technique and fluorometric evaluations were used. We conducted research in the period 2015-2020, sampling was carried out in spring, summer, autumn. Thus, we studied the circulation (in miniature) of changes in the protective properties of humic substances, depending on a large number of factors.

How to cite: Dinu, M.: Interaction of ions of heavy metals and organic toxicants with humic substances in system ‘atmospheric precipitation - lysimetric waters - lake waters’ of the Reserve of the European Territory of Russia: climatic, technogenic, geochemical fact, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9724, https://doi.org/10.5194/egusphere-egu21-9724, 2021.

The emission of metal ions in the environment has increased in recent times and since metal ions are not biodegradable, they belong to the cumulative toxins. Contamination of the environment with metal ions poses a serious danger to the entire ecosystem, agricultural production, quality of food and water, as well as to the health of humans and animals. This study investigates sorption as one of the processes which can be used for pollutants removal and efficiency of certain sorbent materials. Specifically, we focus on development and validation of non-linear Langmuir model and non-linear Freundlich model. Their application in sorption experiments is examined by applying different error functions and statistical methods which are employed to calculate the error divergence between observed data and predicted data of sorbate-sorbent system. Presented non-linear sorption models are developed by using programming language Fortran, and the data analysis is obtained by using different tools and packages in programming language R. Many authors are using linear sorption models in the way that they would linearize non-linear sorption models. It is evident that linear sorption models are used due to their simplicity in parameters estimation. We use approach of trying different algorithms and tools in programming language R in order to find the best objective function. This study shows that both non-linear Langmuir model and non-linear Freundlich model can be used for experimental data representation. The results also denote that better estimation and the better fit is given by Langmuir model due to divergence in error functions and graphical representation itself. The choice of sorption model has a great influence on the prediction of solute transfer and great care should be taken in selection of convenient approach.

How to cite: Koš, A. and Kuráž, M.: Mathematical Modeling of Sorption on Novel Sorbent Materials, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10005, https://doi.org/10.5194/egusphere-egu21-10005, 2021.

Inorganic polymers (IPs) are alkali activated aluminosilicate materials. Research on the synthesis of alternative cementitious materials such as IPs receives substantial attention not only for their physico-chemical properties that they acquire but for being cost-effective components of the future toolkit of sustainable construction materials (Provis, 2018; Vavouraki, 2020). In addition to potential uses of alkali activation materials for the disposal of industrial solid wastes and by-products, there is a great scientific interest in deploying IPs for environmental remediation purposes (Rasaki et al., 2019). In particular IPs can possess application value in pollution treatment of immobilization of toxic (and/ or nuclear) wastes, both inorganics and organics (Ji & Pei, 2019). Green sustainable aluminosilicate-based adsorbents may facilitate the elimination of toxic metal and organic pollutants from water and/ or wastewater (Tan et al., 2020). IPs are considered low-cost sorbents not only for successful recycling of waste materials but also considering added-value materials for the removal of heavy metals from aqueous solutions. However limited number of studies examines waste-slag-based IPs for the removal capacity of heavy metals.

The aim of this study is to synthesize IPs from ground waste concrete and industrial slags and investigate their uptake capacity for heavy metals from aqueous solutions. The calcite-bearing and industrial-slags IPs as sorbent materials were examined for the uptake of solely Cu(II), Zn(II) and, Pb(II) and also or along with competitive aqueous solutions. Kinetics and equilibrium experiments were performed and analytical techniques involving XRF, XRD, FTIR, SEM/ EDS and XPS were used for the characterization and morphology analysis of the produced IPs.

References: Ji & Pei, 2019. J. Environ. Manage. 231, 256–267; Provis, 2018. Cem. Concr. Res. 114, 40–48; Rasaki et al., 2019. J. Clean. Prod. 213, 42–58; Tan et al., 2020. Environ. Technol. Innov. 18, 100684; Vavouraki, 2020. J. Sustain. Metall. 6, 383–399.

How to cite: Vavouraki, A.: Inorganic polymers of ground waste concrete and industrial waste slags as a low-cost sorbent of heavy metals, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14828, https://doi.org/10.5194/egusphere-egu21-14828, 2021.

The aim of the research was to identify potential processes influencing the accumulation and persistence of pesticides in soils.

The pesticides have been the most effective and modern method of counteracting threats to the yield from biotic factors, despite numerous controversies related to their negative impact on the environment. A natural storage of all types of contaminations in ecosystems, including pesticides, is soil. Pesticides behavior in soils is determined by various processes including volatilization, uptake by plants, leaching and runoff, sorption and binding by soil components, chemical degradation by hydrolysis, oxidation – reduction and photolysis processes as well as degradation by soil microorganisms [2]. Many of these mechanisms depend on molecular properties of individual pesticides and accompanying substances occurring in plant protection products. A strong influence on behavior of pesticide in the environment is related to their formulation/composition. The accompanying substances such as synergists, buffers, activators, organic solvents, adsorbents, fillers, or adjuvants may significantly modify the physical and chemical properties of the active substance. According to numerous studies, these compounds have an effect on availability, durability, mobility, and, in consequence, biologic characteristics of the pesticides in soils [4, 5].

According to the literature data, accumulation of pesticides in soils is strictly dependent on the sorption - desorption mechanisms with soil organic and mineral particles. The extent of these processes depends on the properties of soil and the compounds such as molecular size, shape, configuration, structure, functional groups, solubility, polarity, polarizability, charge distribution of interacting species and acid-base nature [3]. Moreover, the pesticides adsorption involves two phases including (1) macroscopic process (macro sorption) which includes surface sorption where the  the equilibrium constant is reached relatively fast as well as (2) microscopic process (micro sorption) which requires longer contact between soil and pesticide, related to diffusion of pesticides into inner active layers. Both processes lead to pesticide enclosing in 3D - structure of the organic matter or in interpocket space of clay minerals [1-5].

The number of processes that determine the behavior of pesticides may occur simultaneously or individually, nevertheless, it is important to identify them in detail in terms of counteracting soil degradation or undertaking appropriate soil remediation processes.

Literature:

1. Bejger, R.; Włodarczyk, M.; Waszak. M.; Mielnik, L.; Nicia, P. The adsorption of pendimethalin by peats and lakes bottom sediments. Ecol. Chem. Eng. A. 2014, 21(1), 79-87.

2. Pignatello, J. Dynamic interactions of natural organic matter and organic compounds. J. Soil. Sediment. 2012, 12, 1241-1256.

3. Mamy, L.; Barriuso, E. Desorption and time-dependent sorption of herbicides in soils. Eur. J. Soil. Sci. 2007, 58, 174–187. 

4. Ukalska-Jaruga, A.; Smreczak, B.; Siebielec, G. Assessment of Pesticide Residue Content in Polish Agricultural Soils. Molecules. 2020, 25, 587doi:10.3390/molecules25030587.

5. Włodarczyk M. Influence of formulation on mobility of metazachlor in soil. Environ Monit Assess. 2014, 186, 3503–3509.

Acknowledgements:

This work was supported by the National Science Center (NCN) Poland (project No 2018/31/B/ST10/00677 “Chemical and spectroscopic properties of soil humin fraction in relation to their mutual interaction with pesticides").

How to cite: Bejger, R., Ukalska-Jaruga, A., Ćwieląg-Piasecka, I., Weber, J., Mielnik, L., Jamroz, E., Jerzykiewicz, M., Dębicka, M., Bekier, J., and Kocowicz, A.: Identification of potential pesticide accumulation processes in soil, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15364, https://doi.org/10.5194/egusphere-egu21-15364, 2021.

Biomass collection and processing are important steps in the implementation of an integrated algal system that allows downstream processing for the production of biofuels and other valuable bioproducts. In attached systems, the algal biomass is directly inoculated onto solid carriers and biofilm is formed by providing the required nutrients. Biofilm is a complex community of microorganisms including microalgae bacteria, and protozoa, which are adhered to a submerged surface. Until today, various types of substrates have been studied such as stainless steel, polymeric materials (plexiglass, PVC), natural polymers (cotton, cork), lignocellulosic materials (pine sawdust, rice husk). The above materials have different textures, roughness and surface properties. In this study, biochar produced from olive kernels by pyrolysis at 400^oC was tested as solid support for Chlorococcum sp. cultures. The substrate used was BG-11 enriched with 1/3 nitrates. After 15 days of cultivation, the biomass attached on biochar was determined, while pH, cell concentration, total suspended solids, chl-a, anions, total proteins and carbohydrates were measured in the liquid. The presence of biochar enhanced algal growth and the biomass attached in biochar was about 3 times higher compared to the biomass grown in the control unit (without biochar carriers). The preliminary findings of this work  shows that biochar is capable to attract algal cells and to promote algal growth.

How to cite: Tsavatopoulou, V. D. and Manariotis, I. D.: Biochar as solid carrier for supporting algal biofilm, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9110, https://doi.org/10.5194/egusphere-egu21-9110, 2021.

Designing of materials for effective uranium removal remains an open challenge. In the present work, we present a one-step co-condensation synthesis of a phosphonate functionalized ordered mesoporous silica (OMS-P). This novel material was characterized by various physicochemical methods (HR-TEM, SEM, N₂sorption, XPS, solid NMR, low-angle XRD, and FTIR) and its ability to remove U(VI) by adsorption from aqueous solutions was studied. The maximum adsorption capacity reached 345 mg/g in 10 minutes, the highest reported up to day for silicas at pH = 4 and almost four times higher than for the unfunctionalized silica. Even more interestingly, the coexistence of other cations, such as Eu(III), did not affect adsorption capacity and selectivity. The adsorption results were evaluated based on various theoretical models in order to conclude regarding the kinetics. Moreover, the main interactions responsible for the increased U(VI) removal efficiency and in general the role of surface chemistry were analyzed by spectroscopic characterizations of OMS-P before and after adsorption.

How to cite: Giannakoudakis, D. A., Anastopoulos, I., Barczak, M., Αntoniou, Ε., Terpiłowski, K., Sigarikar, E. M., Shams, M., Coy, E., Bakandritsos, A., Katsoyiannis, I. A., Colmenares, J. C., and Pashalidis, I.: Supreme and selective capture of one of the most dangerous metal, URANIUM, by phosphonate-functionalized ordered mesoporous silica: surface chemistry matters the most, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-16251, https://doi.org/10.5194/egusphere-egu21-16251, 2021.