(643c) Synthesis and Characterization of Novel Sorbent for Boron Removal

Excess intake of boron containing water can pose serious problems on living species. Traditional technologies are limited by insufficient efficiency especially for trace boron removal. In this study, a novel sorbent was developed by functionalizing a kind of natural biopolymers, chitosan with N-methylglucamine (NMDG) via atom transfer radical polymerization (ATRP) method, as well as the microscale properties and sorption mechanism of the sorbent were investigated. A series of batch sorption experiments were conducted to investigate the boron sorption behaviors of the synthesized chitosan based sorbent. Results show, comparing to raw chitosan, the boron uptake capacity of the NMDG modified chitosan is significantly enhanced. The maximum sorption capacity of modified chitosan is determined to be 1.09 mmol B/g sorbent while that of raw chitosan is only 0.27 mmol B/g sorbent. Isotherm study indicates the sorption can be described well by Langmuir isotherm model. The equilibrium time of boron sorption is achieved in less than 10 h. Moreover, the optimum pH for boron removal is found to be in the range of 6 to 7.5. Furthermore SEM, FTIR and XPS have been used to observe and characterize the microscale properties of the sorbent as well as to probe the interaction mechanism between boron and sorbent. Results show the complexation between boron and active sites of the sorbents possibly played an important role in sorption process.