- 1CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; LABBELS – Associate Laboratory, Braga, Guimarães, Portugal.
- 2School of Agriculture, University of Lisbon, 1349-017 Lisbon, Portugal; LEAF (Linking Landscape, Environment, Agriculture and Food) & TERRA (Laboratory for Sustainable Land Use and Ecosystem Services),
Illegal industrial discharges of heavily contaminated effluents are of great concern as they occur under uncontrolled conditions. In most cases these effluents are very acidic, a cocktail of organic and/or inorganic molecules, eventually with high concentrations of heavy metals. This project aims the design of sustainable permeable biobarriers, defined by fungal and bacterial biofilms supported on low-cost materials as natural zeolites or residues of agro-forestry activities to be applied in environmental restoration and to reintroduce the used elements/molecules into the circular economy processes.
The present study is focused on soil protection by permeable barriers made of 13X zeolite or vermiculite, supporting a fungal isolate collected near a river basin, genetically typed by DNA sequencing and identified as belonging to the Alternaria alternata species. These matrices were tested to retain chromium and lead and were investigated at different sorbent dosages, pH and initial metal concentration.
Batch equilibrium and kinetic sorption experiments were performed using both metals solutions, with concentrations among 50 mg L-1 and 200 mg L-1, at pH 2 and 5, between 2 h and 288 h. To evaluate the sorption equilibrium, eight isotherm models were fitted. Better adjustments were observed for the Redlich-Peterson and the Khan models, for the adsorption of chromium (R2 = 0.99) and of lead (R2 = 0.99), respectively. The sorption kinetics was evaluated using three models – Elovich, Pseudo first order and an empirical power function. The retention of lead was almost instantaneous and the empirical power function described better the sorption kinetics of chromium (0.89 < R2 < 0.99). In addition, flow experiments were performed with effluents of both metals (50 mg L-1) at pH 2 and 5, for about 90 h. Results revealed a high retention of chromium, and a weak retention of lead, for low pH values. FTIR analyses to the columns samples revealed that clay minerals have an important role in the retention of both metals.
How to cite: Tavares, T. and Brito, A.: Sustainable biobarriers for soil protection– rehabilitation and recycling, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10863, https://doi.org/10.5194/egusphere-egu25-10863, 2025.
