Isotherm and Kinetic Evaluation of Dialium guineense Seed Husk and Its Modified Derivative as Efficient Sorbent for Crude Oil Polluted Water Treatment

Raw Dialium guineense seed husk (DGSH), a native west African plant, and its phosphoric acid modified form (PA-DGSH) were utilized as cheap natural organic sorbent for petroleum sequestration from aqua media. Characterizations of sorbents prepared were carried out by FTIR, BET surface area analysis, and TGA. Significant changes in the surface properties were observed on the sorbent after acid treatment. Different experimental factors such as sorbent dosage, temperature, petroleum concentration, contact time, and pH were used to assess the effectiveness of petroleum removal by DGSH and PA-DGSH using batch sorption methodology. The experimental factors affected the uptake of crude oil on both sorbents. The Langmuir model gave the best fit to the sorption of crude oil on DGSH with R-2 of 0.994 and chi(2) of 0.17. The Freundlich was applicable to PA-DGSH with R-2 of 0.991 and chi(2) of 0.23. The constant parameters of Freundlich and Langmuir revealed good affinity between both sorbents and crude oil molecules. The pseudo-first-order kinetics gave better fit than the pseudo-second-order model in the kinetic analysis, and intraparticle diffusion model showed that the sorption of crude oil on both sorbents was mainly a surface mechanism. Both DGSH and PA-DGSH were found to be useful sorbents for the treatment of oil spill-polluted waters.