Research On Removal Efficiency Of Chromium About Industrial Wastewater Containing Chromium By Cu-C Heterogeneous Plate Pulsed Electric Field-co-precipitation Method

The main existing forms of chromium in water are Cr6+ and Cr3+, Cr3+ is in the presence of cation, Cr6+ is usually in the form of anionic groups, Cr3+ and Cr6+ in water accounted for 20% and 80% of total chromium respectively. The toxicity of Cr6+ is 100 times as much as Cr3+, when the intake of Cr6+ is more than 0.1mg/L, it will lead to human poisoning.At present, the commonly used methods of removing chromium in domestic and overseas, according to their mechanism of action can be divided into:physical method, chemical method, biological method, electrolytic reduction method, in which the chemical reduction precipitation method is widely used.In this thesis, new ideas and new methods with Cu-C heterogeneous plate pulsed electric field-co-precipitation method were explored to remove chromium in industry wastewater, the removal mechanism of this method is discussed theoretically, the mechanism is summed up as "three effect" and "five process", we carried out the research that the effect of the pulse voltage, action time, the amount of Fe2+, duty ratio, the electric field cycle on chromium removal efficiency of the Cu-C heterogeneous plate pulse field-co-precipitation method; we also carried on the comparative study of chromium removal efficiency for three different plate material(Cu-C、C-Cu、Cu-Cu) in aspects of the pulse voltage, action time, pulse rate; and compared this method with chemical precipitation in governance cost of chrome removal.In the study of the thesis:1.the chromium removal efficiency of the Cu-C heterogeneous plate pulse field-co-precipitation method was increased with the increase of the time of action, the decrease of the duty ratio and the increase of the amount of Fe2+. The optimum process parameters are as follows:pulse voltage is 75 V, cycle is 30ms, duty cycle is 10%, mFeSO4.7H2O：mCr6+=1：1, action time is 4 min, the removal rate of chromium under this conditions is as high as 99.92%.2. there is potential difference between the materials of different electrode materials, the potential difference is conducive to the removal of chromium, and the reverse potential is not conducive to the removal of chromium.3. processing 1 ton of industrial wastewater containing chromium, Cu-C heterogeneous plate pulsed electric field-co-precipitation method required to join the content of Fe2+ is 1/15 of that of chemical precipitation method, the cost is 1/3 of that of chemical precipitation method, the processing time is 40% of that of chemical precipitation method.The research shows that the Cu-C heterogeneous plate pulse field-co-precipitation has a good application prospect because of its high efficiency, low cost, environment friendly and so on.