Adsorptive filtration of low‐concentration lead with wet‐laid filter media made from nano‐TiO₂ decorated cellulose fibers

Abstract

Background TiO2‐cellulose composite fibers are a new type of bio‐sorbent combining natural polymers and nanoparticles. However, their batch adsorption capacity is limited. Here mesoporous TiO2‐cellulose composite fibers were synthesized and a filter medium was subsequently made from them to remove lead continuously by dynamic adsorption. Results TiO2‐cellulose composite fibers with rough hierarchical surface structure were fabricated by in situ growing mesoporous TiO2 on cellulose fibers via microwave‐facilitated hydrolysis. The composite fibers were then wet‐laid into a filter medium to remove low‐concentration Pb2+ in water through adsorptive filtration. The breakthrough curves were found to be better predicted by the dose–response model originally established for a fixed column bed. With a volume of merely 2.07 cm3, the medium can treat 150.0 L of water containing 50 ppb lead to the drinking water standard. The filter performance was improved by incorporation of small non‐functional glass fibers to minimize the pore size and its distribution. The medium was also Pb2+ selective over co‐existing cations, and could be easily regenerated and reused without reduction in performance. Conclusion The filter medium fabricated by nano‐TiO2 decorated cellulose fibers showed enhanced adsorption capacity for lead through adsorptive filtration. Such filter beds have high potential for toxic micro‐pollutant removal from drinking water. © 2017 Society of Chemical Industry