KOH modified Thevetia peruviana shell activated carbon for sorption of dimethoate from aqueous solution.

Modified Thevetia peruviana shell activated carbon for sorption of dimethoate from aqueous solution derived with potassium hydroxide (KOH) was studied at different concentrations for its potential application in water treatment. The batch sorption was investigated using dimethoate solution of 10-100 mg/L concentrations. Proximate analysis was determined and changes on the surfaces and structure of the TPS were characterized after chemical activation with KOH using XRD, FTIR, SEM-EDAX, pHpzc, BET. The quantum chemical calculation for dimethoate yielded molecule associated energies of -9.8421 (HOMO) and -2.3879 (LUMO) and a total energy of -53,376.2. The kinetic of the sorption was modeled which indicated the sorption equilibrium time as 90 min and pseudo-first order kinetics model showing R2 = 0.994 provided a better description of the process. Analysis of sorption equilibrium revealed that the data fitted well to Freundlich sorption isotherm model (R2 = 0.966), indicating multi-layer sorption of dimethoate on the surface of sorbent. The sorption of dimethoate onto KOHTPS shows 92.60% removal efficiency.