Reseach Of Adsorbent For Aarsenic Removal From Drinking Water

Arsenic is one of the most toxic contaminants found in the environment and has been recognized as a toxic element for centuries, and arsenic contamination has become a worldwide epidemic.Chronic exposure to arseniccontaminated drinking water can result in serious health problems. So it is sensible to do reseach for arsenic removal from drinking water to minimize the health impact of arsenic. Adsorption by fixed bed is an efficient way to remove arsenic from groundwater, so the main topic of my task is to develope better adsorbent for arsenic removal.Firstly, the impact of ageing temperature, dosage of titanium, iron and freeze dring was studied in the synthesis of Ti-montmorilonite. Batch experiments were carried on to indicate the effectiveness of arsenic removal. FTIR, XRD, TEM and N2 adsorption-desorption were used to characterize the adsorbent. The results showed that the best synthetic conditions are: the adeing temperature is 80℃; the dosage of titanium is 0.0279mol/2.5gMMT and dring at 0-20℃. The addition of iron into Ti-montmorilonite can improve the performance of the adsorbent which the dosage of titanium is 0.0135mol/2.5gMMT, but do no avail when the dosage of titanium is 0.0279mol/2.5gMMT. Batch experiment showed that Ti-montmorilonite can remove arsenic from water and oxidize As(Ⅲ) efficiently. Arsenic adsorption quantity is 0.815mg/g for As(Ⅲ) and 1.08mg/g for As(Ⅴ) at the equilibrium concentration of 10ppb.Secondly, the Mn-Fe adsorbent was prapered by co-precipitation. The impact of the different ratio of manganese and ferrumiron, calcination temperature, the quantity of base, different process of precipitation and the effect of sodium carbonate in the preparation of Mn-Fe adsorbent on the performance of arsenic removal and Mn dissolution of the adsorbent were studied in this paper.The results showed that the adsorbent has best behavior when Mn: Fe=2:1; the high calcinations temperature make the adsorbent less effective, but no big difference between 80℃and 350℃. The quantity of base, different process of precipitation and the addition of sodium carbonate in the preparation of Mn-Fe adsorbent have little impact on arsenic removal; Less manganese ion was stripped out by using the adsorbent which was prepared by mixed base solution(Na2CO3, NaOH) than that of sodium hydroxide only; also the material with 2:1 ratio of manganese and iron had least stripping of manganese. Finally, we have gained sorbing material with good behavior of arsenic removal and less manganese ion stripping. Arsenic adsorption quantity is 2.26mg/g for As(Ⅲ) and 3.98mg/g for As(Ⅴ) at the equilibrium concentration of 10ppb.Thirdly, breakthough test of GTO arsenic removal adsorbent was carried on. The testing water with four different concentrations(120ppb,220ppb,290ppb and 410ppb), which is sampled from ShanYin town of Shuozhou section of Shanxi province, is charactered with low breakthrough volumn which is due to the alkalescence and high content of organic substance. And the operating capacity is 10500Vb,5800Vb,4300Vb and 3800Vb for the different concentration of arsenic of the inlet water.