New ceramic membrane for Phosphate and oil removal

Abstract

A novel hybrid ceramic membrane incorporated with activated carbon (AC) was prepared and tested for two distinct end uses: a) phosphate removal from treated sewage effluent (TSE), and b) oil removal from saline water. The membrane was prepared by incorporating the cheap and high surface area powdered AC (10 wt%) within an alumina (Al2O3) framework. AC incorporation enhances the adsorptive properties of the hybrid membranes and create a tortuous matrix of micro- & nano-channels, that eventually improved the overall porosity and total pore area of the membrane by 90% when compared with unmodified alumina membrane. Moreover, the modified ceramic membrane showed an increase of 71% in its hydrophilicity and an increase of 45% in its oleophobicity when compared to unmodified alumina membranes. Due to the enhancement in the porosity and hydrophilicity, the hybrid Al2O3/AC membrane showed a higher permeate flux in comparison with the unmodified membrane. The phosphate removal capacity of the modified membranes was evaluated by the treatment both of model solutions and real TSE. The novel Al2O3/AC membranes exhibited almost complete phosphate removal at 30 ppm phosphate concentration in the TSE while maintaining a high permeate flux of 18.9 L/m2.h (LMH) compared to 2.8 LMH for the unmodified alumina membranes. The prepared Al2O3/AC membrane has demonstrated oil removal efficiency between 91% and 99% at emulsified oil concentrations ranging between 500 and 5000 parts per million (ppm). The modified membrane showed improved anti-fouling behavior during the filtration of oil and real TSE when compared with unmodified membrane. During the fouling resistance tests with emulsified oil, the Al2O3 membrane showed a noticeable normalized flux drop of about 60% after the sixth filtration cycle while only a slight decline in the normalized flux was found for Al2O3/AC membrane. The results of this work showed that the novel Al2O3/AC membrane can be used for the efficient removal of phosphate residue from TSE, and pretreatment of oil-containing wastewater.