Hits:Updated:2016-08-04 14:08:15【Print】
| Electroplating is the use of chemical and electrochemical methods in metal or other material deposited on the surface of various metals. Electroplating wastewater mainly from floor cleaning water, drop, leakage, seepage plating solution and bring out the waste plating solution and the like. Electroplating wastewater from the electroplating industry ingredient produced very complex, in addition to cyanide (CN-) waste water and acid-base wastewater, heavy metal wastewater electroplating wastewater industry potentially great danger categories, heavy metal ions in electroplating wastewater is an important pollutant, It can cause serious pollution to the environment. According to incomplete statistics, China electroplating factory wastewater discharged every year about 40 billion m3. Electroplating wastewater treatment widespread attention at home and abroad, we have developed a variety of management techniques, such as toxic into non-toxic, harmful into harmless, recovery of precious metals, water recycling technology, can eliminate and reduce emissions of heavy metals . With the increasing rapid development of electroplating industry and environmental requirements, recognized good electroplating wastewater treatment technology are the following: chemistry, membrane separation technology, chelating precipitation, HR type (series) chromium removal machine, biochemical , high-voltage pulse electric coagulation plus diatomite integrated technology. Fly ash, slag and other industrial waste generated in the production process, abundant, cheap and readily available. In this study, mainly chemical and physical adsorption process, investigate industrial waste fly ash, cinder, bentonite and zeolite four kinds of electroplating wastewater treatment agent for removal of heavy metal ions, in addition to the effect of screening out fairly and economical treatment agent, reducing processing plating the cost of waste water, provide a theoretical basis for the electroplating wastewater treatment. 1. Materials and methods 1.1 Materials Heavy metals treatment agent: fly ash, cinder, bentonite, zeolite; electroplating wastewater: Zhaoqing collected from an electroplating factory, measured heavy metals in waste water background values are: Cu2 + concentration 100.99mg / L, Zn2 + 17.82mg / L, Cr6 + 1.60mg / L, Ni2 + 70.31mg / L, Pb2 + 0.29mg / L, in which Cu2 +, Zn2 +, Ni2 + concentration [excessive levels of "integrated wastewater discharge standard" (GB8978-1996)]. 1.2 Test Method This test uses a single design factors and three levels, each set of three treatment agent dosage levels were 0.3,0.6,0.9g / mL water, in an amount ranging reference Zeng Fang, Hu Tao, etc. The amount of levels, together with the non-treatment agent blank control (no treatment agent is added, other steps the same), a total of 13 treatments, three replicates per treatment. Four kinds of treatment agents were added 25mL electroplating wastewater was allowed to stand 10min, then 1mol / L NaOH to adjust the pH to 7.0 to 7.5, a slow oscillation 15min, filtered, and the filtrate was determined +, Zn2 +, Ni2 + concentration of Cu2. In terms of the treatment agent for Cu2 +, Zn2 +, Ni2 + removal rate (%), calculated as follows: 2 Results and Analysis 2.1 Effect of treatment dosage of Cu2 + removal efficiency Learned from Figure 1, three dosage levels of fly ash and no significant difference between the removal of Cu2 +, is within the range of 95.79% ~ 96.71%, both for Cu2 + removal closer, between the bentonite and zeolite between. Cu2 + removal rates were significantly different three dosage levels of bentonite and zeolite, Cu2 + removal rate increases with dosage increases significantly, ie 0.3g <0.6g <0.9g. When dealing with dosage level of 0.3g, the fly ash, cinder, zeolite three treatments Cu2 + removal rates were all significantly greater than the bentonite removal; the amount of 0.6g, the fly ash and cinder removal is higher than bentonite removal, removal and less than the zeolite; an amount of 0.9g, the bentonite and zeolite are higher than the removal of fly ash and cinder removal. Overall, bentonite electroplating wastewater Cu2 + removal worst zeolite Cu2 + removal best. Removal of fly ash and cinder fairly between bentonite, zeolite is between the two. Concentration but after plating wastewater containing Cu2 + still not reached the national emission standards 0.5mg / L, the amount of treatment agent described is still low. |
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