Application of Eriobotrya japonica (Thunb.) Lindley (Loquat) seed biomass as a new biosorbent for the removal of malachite green from aqueous solution

摘要

A new biosorbent, Eriobotrya japonica (loquat) seed biomass, has been investigated in order tonremove malachite green (MG) from aqueous solutions. The factors affecting the biosorptionnprocess such as adsorbent dosage, pH of the solution and contact time were studied. The resultsnshowed that as the dose of loquat seed increased, the percentage of MG biosorption decreasednaccordingly. The experimental data suggested that the maximum pH for efficient biosorption ofnMG was 5.0. The biosorption process was relatively fast and equilibrium was achieved after aboutn60 min. Freundlich and Langmuir adsorption isotherm models were used for adsorptionnequilibrium data and based on the Langmuir isotherm plots the maximum bisorption capacityn(Qmax) value was calculated to be 57.47 mg/g at 208C. The biosorption kinetics was determined bynfitting pseudo-first-order and pseudo-second-order kinetic models to the experimental data, withnthe second-order model providing the best description of MG biosorption onto loquat seed.nVarious thermodynamic parameters such as free energy change DG 0, enthalpy of sorption DH 0nand entropy DS 0 were estimated. The positive value of DH 0 and negative values of DG 0 show thensorption process is endothermic and spontaneous. The positive value of DS 0 shows the increasednrandomness at the solid–liquid interface during the biosorption of dyes onto loquat seed.