Investigation into the adsorption of methylene blue and trimethoprim onto modified peanut husk in single and binary systems

The remediation of contaminated water sources is of great importance owing to the integral role of clean water in the normal functioning of the ecosystem. In this study, the removal of methylene blue and trimethoprim (TMP) in water was assessed using a low-cost adsorbent from peanut husk modified with potassium permanganate. Characterization of this adsorbent (labelled as PNK) suggests it to be a crystalline material endowed with functional groups which may have supported its good efficiency towards the studied pollutants. The results from the adsorption studies showed that the adsorption of PNK towards MB and TMP could reach up to 270 and 25 mg g^–1 at ambient environmental conditions. The dependence of the reaction processes on the active sites on PNK and its interactions with the molecules of the pollutants could be inferred from the observation that the pseudo-second order kinetic model better described the kinetic process for the uptake of MB whereas the Elovich equation was more appropriate for the uptake of TMP. The results from nonlinear fitting isotherm models suggest that the uptake of both pollutants occurred via the formation of multilayer adsorption on an heterogenous surface. The feasibility of PNK for the practical remediation of these pollutants was confirmed via the column method. The likely role of mass transfer mechanisms involving both film mass transfer and porous diffusion was deduced from the results of intraparticle diffusion equation. Summarily, PNK exhibits good removal abilities towards the studied pollutants and has good prospects for practical applications.