Hydrogel-rice husk biochar composite as an adsorbent for the removal of phenol and PNP from aqueous solutions

Poly(acrylamide)-rice husk biochar [p(AAm)-RHB] hydrogel composites (HBC-RH) were used to eliminate phenols. The characterization of prepared composite was investigated by using SEM, TEM, TGA DSC, and FTIR. Based on our findings, the highest removal of phenol and p-nitrophenol (PNP) was found as 82.2% and 84.6% in 50 mg/L solution at pH = 7, respectively. The results revealed that the kinetic data were best fitted by pseudo-first-order for phenol and pseudo-second-order for PNP. To be concluded that the Temkin model perfectly described the removal of phenol and HBC-RH can be widely applied for various containments.