Performance Study Of Coagulate Arsenic Removal By Poly-Titanium-Ferrous Chloride

Many countries have a worldwide water contaminated with arsenic. We never give up to develop the effictive, simple and economical methods of arsenic remove. From previous researches, titanium salts have advantages on coagulation arsenic removal than traditional iron and aluminum salts. Titanium salts have a strong ability of coagulation, and also can be recycled as a water treatment coagulant. As for the present study, to find the most simple and effictive method of remove As??? is one of the hot spots in the study of arsenic removal. In this paper, we use titanium and ferrous with different methods to prepare poly-titanium-ferrous chloride. Specific studies are as follows:1) Using NaOH as alkalizer introduced by dripping slowly to prepare poly-titanium-ferrous chloride?PTFC?. This thesis makes a primary research on coagulation dearsenic mechanism of a new self-made coagulant. We make a concrete analysis of the new self-made coagulant, and comparing with the traditional single metal salt coagulants. The feasibility of factors including different ratio of titanium to ferrous,different basifying agents, basicity, the solution's pH values, co-existing ions on arsenic removal by the PTFC coagulation were investigated. The results of experiments showed that without changing pH in the coagulation process, As??? removal efficiency increased with increasing dose of PTFC, and As??? removal efficiency by PTFC was high at weak acid conditions. Arsenic removal by PTFC was obviously promoted with aerated oxidation at 60 m L/min with twenty minutes. When titanium-ferrous amount-of-substance ratio is 5:5,B=0.6, arsenic removal rate can reach 93.05%. The effect of alkalizer on As??? removal by PTFC was relatively weak. The dihydrogen phosphate ions have no obvious effect on arsenic removal, while presence of silicate anion in the solut Aion would significantly inhibit the arsenic removal. Calcium ions play a facilitating role on arsenic removal.2) Using NaHCO₃ and Na₂CO₃ as alkalizers to prepare poly-titanium-ferrous chloride?PTFC?. This thesis makes a primary research on coagulation dearsenic mechanism of a new self-made coagulant. We make a concrete analysis of the new self-made coagulant,and comparing with the traditional single metal salt coagulants. The feasibility of factors including different ratio of titanium to ferrous, different basifying agents, different temperature and methods of prepare, basicity, potassium permanganate oxidation, the solution's pH values, co-existing ions on arsenic removal by the PTFC coagulation were investigated. The results of experiments showed that, in the 50? water-bath heating environment, the poly-titanium-ferrous chloride prepared by solid-liquid mixing withNaHCO₃ has a good effect on coagulation arsenic removal. When the coagulant that TF?9/1?-0.3 adds 20mg/L, arsenic removal rate can reach 94.91%. As??? removal efficiency decreased with increasing dose of alkalinity, and As??? removal efficiency by PTFC is high when B=0.3. Also, As??? removal efficiency by PTFC is high at weak acid conditions. The preoxidation by KMnO₄ plays a batter acceleration role than after coagulant addition when poly-titanium-ferrous chloride coagulate arsenic removal. When KMnO₄ concentration of 0.6mg/L, arsenic removal rate can reach 92.18% coagulate by coagulant TF?9/1?-1.1. The dihydrogen phosphate ions and silicate anion in the solut Aion would significantly inhibit the arsenic removal. Calcium ions play a facilitating role on arsenic removal.As for the present study, many reports pay attention to polymeric metal coagulant preparation by iron and aluminium salts. while using TiCl₃ and Fe Cl2 to prepare polymeric metal coagulant is only a few reports in the literature. In this article, through systematic study we found that, polymeric metal coagulan has a good effect for removal of As???when preparation by titanium and ferrous salts. Aeration and KMnO₄ oxidation have been increased significantly to coagulate removal of As???. And calcium ions play a facilitating role on arsenic removal.