Phosphate removal from solution by composite of MCM-41 silica with rice husk: kinetic and equilibrium studies

Research Abstract

In this study, rice husk and cetyltrimethylammonium (CTAM) bromide were used to prepare MCM-41 silica on the surface of rice husk to make composites. The synthetic composites were synthesized under hydrothermal conditions and characterized by powder X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and tested as sorbents for phosphate from aqueous solution. The effects of different experimental parameters such as contact time, initial phosphate concentration, solution pH, adsorbent mass, and the presence of competitive ions on the adsorption performance were investigated. The results showed that phosphate uptake kinetic was fast and equilibrium was achieved after 30 min. The uptake of phosphate was highly pH dependent. Studies on the effects of competing ions indicated that phosphate uptake and Kd values decreased in the presence of CO3-2 and NO3-, with little affected by SO4-2 ions. The adsorption of phosphate by composites of rice husk with MCM-41 could be described will by the Langmuir isotherm equation. Adsorption kinetic data correlated well with pseudo-second-order model indicating that the adsorption process might be chemical sorption. "

Research Keywords

Porous Materials,Nanocomposites, water purification