Study On Sulfide Precipitation-Ferrite Coupling Heavy Metal Wastewater Treatment

The rapid development of industry has generated a lot of heavy metal wastewater which will result in not only a waste of resources and energy but also the secondary pollution on the surrounding environment in an irreversible way because of the concentration of heavy metals properties if it isn’t handled properly. Therefore,how the heavy metal wastewater which has been treated through scientific methods can meet the standard of emission as well as become innocuous and resourceful has been heatedly discussed in society and academic field. With the purpose of providing the experimental evidence of the practical applications for the wastewater treatment and heavy metal sulfide precipitation- Ferrite Process, this thesis is carried out to study the heavy metal wastewater sulfide precipitation- Coupled Method Ferrite processing technology and to determine the optimum operating conditions of the sulfide precipitation- Ferrite coupling process technology.From the perspective of the process and effect of treatment, this thesis which takes into consideration the laboratory wastewater(including pollution factors Cu²⁺,Pb²⁺, Zn²⁺) aims to carry out the study of the sulfide precipitation- Experimental Study of Ferrite Coupled water treatment technology for heavy metal wastewater treatment. The results can be concluded in the below.1. On account of the analysis of the water treatment technology of sulfide precipitation- Basic Ferrite coupling mechanism, this thesis selects the p H value,Na₂S: Me²⁺ molar ratio, Na₂S: Fe SO₄ dosing ratio, aging time---the four kinds of test factors which are marked as F1, F2, F3, F4 respectively. Through the analysis of the orthogonal experimental design and water quality, the sequence of the every factor notably affecting on reaction can be indicated as follows: p H value> Na₂S: Me²⁺molar ratio> Na₂S: Fe SO₄ dosing ratio> aging time;2. The study has shown that the concentration of heavy metal ions has a negative correlation with the increasing p H value. But if the p H value exceeds a certain limit,the re-precipitation of heavy metals will be precipitated in an alkaline environment which also be verified by the effect of effluent treatment. Under the experimental conditions, it can be concluded when the p H value is 9, the three kinds of heavy metals can achieve the optimal effect: they are more than 95%;3. The sulfide precipitation has a remarkable effect on the removal of Cu²⁺, Pb²⁺,Zn²⁺ three heavy metals, and that the Na₂S: Me²⁺ best optimum ratio is 1.2 can be can be obtained through the analysis of orthogonal test results. Considering that the amount of processing and residence time, the best aging time of sulfide precipitation is 10 min by the comparison of the test results;4. The optimum combination of conditions of the sulfide precipitation by the orthogonal experiment- the Ferrite coupling is: p H = 9, Na₂S: Me²⁺ molar ratio of 1.2,Na₂S: Fe SO₄ dosing ratio of 5: 1, aging time is 10 min,and the treated water content of heavy metals is below the “lead and zinc industry pollutant discharge standards（GB25466-2010）”.The sulfide precipitation- Ferrite coupling technique provided by the thesis is an effective one for treating the heavy metal wastewater, offering a new method, new tools and new ideas to solve the wastewater containing heavy metal.