Research On Purification Of Table-water By Activated Carbon Associated With KDF For Remove The Pollutions Of Heavy Metal

Heavy metal often enter the food chain through water pollution which threaten the drinking water. As the food industry was a water-oriented industry, An efficient, security and reliability water purification system is urgent to be researched. The paper studied of the treatment effect on Cr6+, As3+and Cd2+in water at the different conditions such as different initial concentrations, different filter height and different filter speed by water purification system of activated carbon joined with KDF. The objective of this research was to screen out the optimal purification condition which would not only meet the hygienic standard for drinking water, but also ensure treatment efficiency. Likewise, taking Cr6+for example, we studied the saturation adsorption capacity and stability of optimized purification system, and analyzed its removal effect for slightly-polluted water by experiment. The experimental data provides the theory gist and application base for the water purification system of activated carbon associated with KDF using in food industry. The main conclusions are as follows:1. With the limited value of drinking water standard (GB5749-2006) as reference, under experimental conditions, simulated water samples with As3+, Cd2+were treated by activated carbon, the removal rate of As3+, Cd2+were under50%and the effluent concentration of these were over standard. For the test on treatment of Cr+, it has been obtained that the removal rate of Cr6+was from64.8%-84.8%by using activated carbon treatment on condition that the filter height was110mm and the initial concentration was0.125mg/L and the filter speed was from25L/h to135L/h, the treatment has good effect and the quality of output water is quite good to meet drinking criteria. When the initial concentration of Cr6+being0.25mg/L, the filter height being110mm, the filter speed being25L/h, the removal rate of Cr6+was82.8%. In other conditions, most of removal rate were under70%and the quality of output water were over standard. Therefore, the treatment by using activated carbon alone for simulated water samples with As3+, Cd2+and Cr6+did not meet edible requirements and there existed many risks.2. We tried to construct the filtration system by activated carbon joined with KDF, we determined the pollution levels of untreated water in order to achieve the goal for high treatment efficiency, low operation cost, and the safety of table-water. While the filter height being110mm, the filter speed being135L/h, the initial concentration Cr6+and Cd2+being0.25mg/L and0.025mg/L respectively, the removal efficiency were respectively93.2%and82.0%. When the initial concentration of As3+being0.025mg/L, the filter height being170mm and the filter speed being135L/h, the removal rate was96.0%.3. On the condition that filter height being110mm, filter speed being135L/h, and initial concentration of Cr6+being0.25mg/L, the water purification system handled total of2160L simulated water sample on the premise of effluent Cr6+concentrations meet the standard. The adsorption capacity of the water purification system of activated carbon joined with KDF was4.87g/m calculated by unit filter height. Combined backwash, service for usual life and food industry will be much greater than200days in the good quality of the water.4. The dissolved quantity of Cu2+and Zn2+from the water purification system of activated carbon associated with KDF were gradually decreased with higher effluent concentrations of Cr6+, they are in the opposite trend. The concentration of Cu2+and Zn2+were under lmg/L which were the limited value of drinking water hygienic standard. Meanwhile, the precipitation of Cu2+was far less than the Zn2+. On the condition that filter height being110mm, filter speed being135L/h, and initial concentration of Cr6+being0.25mg/L, the precipitated concentration of Cu2+and Zn2+were increased with the increase of pH value and temperature. The reasonable amount of Cu2+and Zn2+are beneficial to human health.5. Under optimized condition, the water purification system of activated carbon joined with KDF has successfully been applied to treatment slightly-polluted groundwater and surface water. After treated all of the water quality indicators were able to meet the hygienic standard for drinking water.