Research On The Treatment Of Copper-Complexion-Bearing Wastewater

The treatment process of chelated copper in electroplating waste water was studied. The engineering feasibility of these processes was also analyzed. According to the chemical properties of chelated copper, experiments were performed in the two aspects: the treatment of organic chelated copper and inorganic chelated copper. Firstly, the removal efficiency and effects of divalent copper (Cu( II)) by Fenton or H₂O₂ assisted iron powder was researched in the treatment of organic chelated copper. In addition, the mechanism of Cu( II) removal by Fenton assisted iron powder was analyzed. Secondly, the removal efficiency and effects of divalent copper (Cu( II)) was investigated in the treatment of inorganic chelated copper by iron powder, iron nanoparticles and heavy metal capturing agent(DTCR). Finally, the engineering feasibility of the processes' application was analyzed. The results are as follows:1. The best conditions for Cu( II) removal by Fenton assisted iron powder were pH=3, H₂O₂: COD=1.5:1, and reaction time=30min. The reaction would be faster when the Fe⁰ particles were smaller and the specific surface area was larger.2. The process of Fenton assisted iron powder had little effect on removing inorganic chelated copper. The mechanism of Cu( II) reduction by Fe⁰ assisted by Fenton was as follows: Cu( II) mainly in dissociation reacted with atomic H which was the product of Fe⁰ corroding. Chelated copper was reduced by Fenton reagent formed by Fe( II) and H₂O₂. In addition, Cu( II) was also removed directly by Fe⁰ and Fe( II), and the product was Cu( II )&Fe(III) hydroxides, which covered the surface of Fe⁰ to slow down the reaction rate.3. Compared with the results of inorganic chelated copper by Fe⁰ assisted by Fenton, in the organic chelated copper treatment, organic radical was oxidated by Fenton, which made Cu( II) free from chelate complex instead of breaking up chelate bound. Therefore, the process could be only applied in organic chelated copper treatment.4. The removal efficiency by iron nanoparticles increased with increasing Fe⁰ nanoparticles addition, and the Cu(II) removal rate could be accelerated by decreasing pH. The Cu( II) reduction rate by Fe⁰ nanoparticles was about 2-3 times as well as that by iron powder because of its large specific surface area. Fe⁰ nanoparticles could be oxidated so sharply that it was difficult to keep, so it should be prepared instantaneously.5. High polymer catching and precipitating agent-DTCR for heavy metal can remove chelated copper in the wastewater effectively. This process could remove several heavy metal ions at the same time.6. Cu( II) concentration in the wastewater treated by iron powder could not meet GB18918-2002 1A discharge standard in despite of its low cost. Fe⁰ assisted by Fenton exhibited well in treating organic chelated copper, it could reach high efficiency at short notice and cost little. So this process can be widely applied to engineering. Fe⁰ nanoparticles showed excellent performance in treating inorganic chelated copper, but its high cost made it hard to be prefered in projects. High polymer catching and precipitating agent-DTCR for heavy metal also performed well, the cost was lower than that of Fe⁰ nanoparticles, so it was feasible in engineering application.