A new material microgel-Fe(Ⅲ) complex was designed for fast and effective removal of cyanobacteria toxin microcystins (MCs) for drinking water safety.  

By immobilizing ions onto the low-cytotoxic microgel, the new complex would bind with microcystins through a fast complexation reaction. Due to the special molecular structure of MCs, seven carbonyl groups and two or more free carboxyl groups on one same ring, the new material show more selectivity for microcystins than the traditional methods such as the powdered activated carbon (PAC). It was also interfered less by natural organic matter during application compared with PAC.  

Under the same condition for both microgel-Fe(Ⅲ) complex and PAC (MC 10μg/ml, microgel-Fe/PAC 0.15 mg/ml), removal efficiency of MCs by microgel-Fe in only 3min was at least 20 percents higher than PAC, which consumed a equilibrium time as long as 16 hours. The new material was also used as a membrane for MC-contaminated water filtration in Lake Taihu and Lake Chaohu. As long as the initial MC concentration was not above 15μg/L, filtration once was enough for MCs control under WHO drinking water safety guideline (MC-LR, 1μg/L) . 

The new material was quite economical, reproducible, biocompatible and environmental -friendly. It gives a new alternative for fast removal of MCs and has a great potential in lager scale application. The related research result was recently published in Water Research [Dai Guofei et al. (2012) Fast removal of cyanobacterial toxin microcystin-LR by a low-cytotoxic microgel-Fe(Ⅲ) complex. Water Research 46(5), 1482-1489. ]. The patent application of this work was also finished.  

This work was supported by grants from “973” Program, Natural Science Foundation of China-Yunnan Project, the National Natural Science Foundation of China and State Key Laboratory of Freshwater Ecology and Biotechnology. It was conducted by IHB Ph.D candidate Mr DAI Guofei et al. whose supervisors are Prof. SONG Lirong and Prof. GAN Nanqin from the Research Group of Algal Resource and Toxicology, IHB.