Rapid elimination of copper ( <scp>II</scp> ), nickel ( <scp>II</scp> ) and chromium ( <scp>VI</scp> ) ions from aqueous solutions by charcoal modified with phosphoric acid used as a green biosorbent

Activated carbon modified by phosphoric acid noted CAa was successfully used as a new low-cost adsorbent for removing Cu2+, Ni2+ and Cr6+ metal ions from artificially contaminated aqueous solutions. Experiments were performed in batches adsorption kinetics isotherms. Scanning electron microscope (SEM) observations well nitrogen adsorption–desorption BET surface area measurement showed the formation of mesoporous with an average pore size 3.1 nm ABET = 678.74 m2 g?1. The data fitted Langmuir model maximum adsorbed amount 238.10 mg g?1 Cu(II), 80.64 Ni(II) 125 Cr(VI) maximal measured N2 231.5337 cm3 STP. experimental variables studied pH, temperature, biomass initial ion concentration. Maximum biosorption observed pH 2. capacity seems to be optimized increasing biosorbent Isotherm adsorptions are agreement models. calculated changes free energy (?G°), enthalpy (?H°) entropy (?S°) confirm that present process is favorable, endothermic spontaneous phenomenon.