Defluoridation in fixed bed column filled with Zr(IV)-loaded garlic peel

Zirconium loaded garlic peel (GP) is an efficient and cheap material for defluoridation of groundwater, while its column run is seldom studied. The purpose of this study was to evaluate the performance of Zr(IV)-loaded garlic peel in the removal of fluoride from a continuous fixed bed column in order to provide guidance for the design and operation of the column reactor. The effects of Zr(IV) ion loading concentration, initial pH, initial fluoride concentration, flow rate and bed depth on the fluorine adsorption performance were investigated. The Thomas model and the bed depth service time model were found to agree well with the experimental data. The practical groundwater samples containing excessive fluoride collected from the Banzhuang Village, Dongguang County, Cangzhou City, Hebei Province, were used to examine the effectiveness in the fixed bed column, and around 1.2 liter clean groundwater was produced to reach the national standard of China (1.0 mg/L) through a 0.5 gram Zr(IV)-GP column, meaning that 2.4 m(3) cleaning water can be obtained based on 1 kg Zr(IV)-GP adsorbent. Elution of adsorbed fluoride can regenerate the Zr(IV)-GP column by using 1 M NaOH, and at least 3 cycles were done to find that a little worsening of adsorption capability. In a word, the cleaning of fluoride-bearing groundwater with a Zr(IV)-GP fixed bed column is expected to be applicable on large scale. The adsorbent is inexpensive, and the cost of 1 kg of adsorbent does not exceed $0.50.