green and eco-friendly synthesis of hydrogel biocomposites for removal of metal ion from aqueous solution: experimental, quantum chemical parameters, and rdg

In this study, the adsorption efficiency of a low-cost biodegradable adsorbent, poly (aac-co-am)/ac biocomposite hydrogel prepared by a green method using free radical copolymerization was studied to remove heavy metals such as copper ions. several analyses of the hydrogel were performed, such as field emission scanning electron microscopy (fesem), transmission electron microscopy (tem), and x-ray diffraction (xrd). the effect of some optimal conditions, such as copper ion concentration, equilibrium time, hydrogel weight, and solution temperature, was studied in the batch model. the adsorption of copper ion increased from 73.25% to 92.91% with a rising weight of hydrogel (0.01-0.1 g/50 ml) but with the increase in weight of the hydrogel, degrease the adsorption efficiency from 27.14 to 219.14 mg/g at a fixed concentration of copper ion 30 mg/l, equilibrium time of 1 h, temperature 25 °c, and agitation speed 150 rpm. finally, as the temperature increases, the adsorption efficiency and removal percentage increase. adsorption equilibrium studies were investigated by langmuir and freundlich isotherm models. the freundlich model provided the result with better efficiency (qe=84.567 mg/g). calculations of non-covalent interaction, rdg, and quantum chemical parameters are used in this study to confirm the real binding between metal ions and surfaces.