Preparation of geopolymer-based inorganic membrane for removing Ni2+ from wastewater

A type of novel free-sintering and self-supporting inorganic membrane for wastewater treatment was fabricated in this study. This inorganic membrane was synthesised using metakaolin and sodium silicate solutions moulded according to a designed molar ratio (SiO2/Al2O3 = 2.96, Na2O/Al2O3 = 0.8 and H2O/Na2O = 19) which formed a homogenous structure and had a relative concentration pore size distribution, via scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analyses. In this work, the Ni2+ removal effect of geopolymer inorganic membrane was studied under different pH value, initial concentration of Ni2+ solutions and initial operation temperature. Results showed that geopolymer inorganic membrane efficiently removes Ni2+ from wastewater because of the combined actions of the adsorption and rejection of this membrane on Ni2+ during membrane separation. Therefore, geopolymer inorganic membrane may have positive potential applications in removing Ni2+ or other heavy metal ions from aqueous industrial wastewater.