Metals in aqueous solutions and real effluents: biosorption behavior of a hemp-based felt

BACKGROUNDIn this study, a hemp-based material in the form of a felt was used to adsorb metals in individual aqueous solutions and in polycontaminated effluents using the batch method. The factors affecting the biosorption process were initial metal concentration, biosorbent dosage, contact time and pH. RESULTSIn controlled conditions, results showed that: (i) the felt exhibited high adsorption capacities towards metals in the following order: Pb > Cd > Cu > Zn > Co approximate to Fe approximate to Ni approximate to Cr approximate to Al approximate to Mn; (ii) no significant differences were observed for the three salts used (sulfate, chloride and nitrate); (iii) the process was rapid: 10 min were sufficient to attain equilibrium; (iv) the biosorption efficiency increased considerably with the increase of the biosorbent dosage; and (v) the adsorption capacities were independent of pH between 4 and 6. The maximum adsorption capacities for Cd, Cu, Zn, Co, Fe, Ni, Cr, Al and Mn were 27.47, 14.64, 10.59, 7.99, 7.85, 7.87, 6.53, 6.38 and 4.55 mg g(-1), respectively. Interesting results also were obtained for real polymetallic effluents. Ecotoxicological tests also confirmed the efficiency of the biosorption to radically decrease the effluent toxicity. CONCLUSIONSBased on these results, hemp-based felt could serve as a novel and efficient biosorbent material for pollutant removal from industrial effluents. (c) 2018 Society of Chemical Industry