Experimental Study of Adsorption Treatment of the Arsenic-containing Rural Drinking Groundwater

摘要

The arsenic-containing rural drinking groundwater was treated by adsorption method in the paper. It was studied that the varieties and dosages of adsorbents, pH value and adsorption time have an effect on removal of arsenic. The experimental results indicated that the rate of arsenic removal is able to reach 91.39% at room temperature and under the condition of neutral pH values, 2.0 g of zeolite as adsorbent and 1 h of adsorption time. The content of arsenic in the treated drinking groundwater can be up to the current national hygiene standards of rural drinking water (<0.05mg /L). Arsenic is a kind of highly toxic protoplasmic poison which may cause cancer, mutation or teratogenicity. Chronically drinking the highly arsenic water will cause a lot of diseases, such as blackfoot disease, neuropathy, vascular injury and so on [1-3]. The toxicity of arsenic is relative to its valence states. Simple substance arsenic is harmless and organic arsenic and arsenic (V) is less toxic. But arsenic (III) is the most toxic to cells, which is able to produce the certain conjugate combining with sulfhydryl group on the protein to exhibit toxicity by preventing cell respiration. In some areas like Inner Mongolia, Xinjiang, Taiwan, Jilin and so on, the content of arsenic in drinking groundwater has reached 0.2～2.0 mg/L and far exceeds the current national hygiene standards of drinking water, which could cause endemic arsenism. Therefore, arsenic removal from drinking water is key measures of prevention of endemic arsenism. At present, several common methods for the treatment of arsenic-containing wastewater include adsorption, coagulation, ion exchange, membrane filtration and so on [6-9]. Adsorption method is easy to operate, but the arsenic waste residue could be formed. Adsorption method is the most widespread and reliable for removing arsenic, because the method has several advantages including high efficiency, little interference, renewability for adsorbent and no secondary pollution [4]. But for adsorption method, the cost of chemical reagent is very high and the compliance ratio is relatively low. In this paper, it have been studied that the arsenic-containing rural drinking groundwater was treated by adsorption method. Also, varieties of adsorbents and conditions of arsenic removal were optimized, which obtained good effects on arsenic removal.