Determination of biosorbent performance of biochar and magnetic biochar derived from animal manure in arsenic remediation from wastewater

Conversion of animal waste into renewable energy and high value added green chemicals are important for protecting human and environmental health and waste management. Among heavy metals, arsenic (As) has a carcinogenic effect on human health through pollution in drinking water. High-performance and environmentally friendly adsorbents are required to remediate arsenic pollution in water. In this study; it is aimed to determine the biosorbent performance of animal waste; cattle manure (M1), chicken manure (M2) and sheep manure (M3) biochars (MB1, MB2, MB3) and magnetic biochars (MMB1, MMB2, MMB3) produced by slow pyrolysis method in the removal of arsenic from wastewater. Magnetic biomass were produced by treating the wastes with FeCl3.6H2O solution, and biomass and magnetic biomass were subjected to TGA analysis and their thermal degradation were investigated. Wastes were pyrolized at a temperature of 450 °C, 10°C/min heating rate, under 100 mL/min nitrogen gas flow for 2 hours, to produce biochars and magnetic biochars. The biochars were characterized by proximate analysis, elemental analysis, BET surface area, XRD, FTIR, SEM/EDX analyses. The effect parameters such as initial As(V) concentration (50, 100, 500, 1000, 2000 ppm), pH (5, 7, 9, 11), temperature (22, 40, 60, 80 °C), mixing rate (0, 150, 300 ppm), adsorbent loading (1:20, 1:40, 1:60) on sorption capacity have investigated. Increase in initial arsenate concentration, temperature, mixing rate, adsorbent dose have found to increase the adsorption efficiency, whereas, increase in pH has found to reduce the adsorption effectiveness. Approximately 100 % arsenate adsorption efficiency has achieved in the experiments carried out with magnetic biochars, irrespective of the changing parameters. Adsorption isotherms have studied with Langmuir and Freundlich models. In order to determine the adsorption kinetics, pseudo-first order and pseudo-second order kinetic models were applied to equilibrium data. The adsorption processes carried out with biochars and magnetic biochars were determined as pseudo-second order. The maximum adsorption capacities of magnetic biochars have calculated as MMB1, 5.30 mg/g; MMB2, 6.00 mg/g; MMB3, 7.14 mg/g. Desorption and regeneration studies were performed in three cycles and adsorption capacities for MMB1, MMB2 ve MMB have obtained as % 44.40, % 49.86 and % 46.00, respectively.