Controlled Oxidation And Flocculation Intensification Of Sulfur-containing Wastewater

The sulfide in sulfur-containing wastewater is toxic and caustic, which may cause serious damage to human health and regional environment. In this paper, the laboratory simulation of sulfur-containing wastewater was used in the single experiment by chemical oxidation. The degradation efficiency of sulfide wastewater treatment and process of sulfide oxidation of O2, Na2SO3 and H2O2 were evaluated to select the best oxidant by using the experimental results with the combination of theoretical calculation of ORP, with the removal rate of sulfide and sulfur production as the indicators. On this basis, enhanced flocculation technology was studied to improve sulfide transformation to sulfur, and enhancement on desulfurization and effective separation of elemental sulfur under different conditions were investigated with sulfur production as main control objectives. In addition, through the study of the reaction system pH, particle size variation and surface morphology of sulfur, fractal dimension of the sulfur floes on the basis of growth model of elemental sulfur, the strengthening mechanism of flocculation system was discussed.The results showed that under the optimal conditions of initial pH was 11, aeration rate was 120 L/h and 4h reaction time, the sulfide removal rate could reach 94.99%, the conversion rate of S2O32- and SO32- were 80.63% and 14.44%, the production of sulfur was zero with air catalytic oxidation methods. Under the optimal condition of initial pH was 5, 5g/L Na2SO3 and 15min reaction time, the sulfide removal rate was 71.79%, the conversion rate of S2O32-,SO32- and sulfur were 40.61%,12.87% and 18.46% respectively. Under the optimal condition of initial pH was 6,9mL/L H2O2 and 15min reaction time, the sulfide removal rate could reach 98.09%, the conversion rate of SO42-, S2O32- and sulfur were 18.86%, 1.93% and 67.94% respectively. Experimental results and theoretical calculation of ORP indicated that three kinds of oxidants were simultaneously multiple parallel reactions and accompanied by the relevant continuous reaction in the desulfurization reaction, which desulfurization efficiency of H2O2 was the highest and the most favorable for the formation of sulfur.With the method of join in PCF-1 and CPAM to hydrogen peroxide reaction system, the conversion rate of sulfur was increased. Under the optimal condition of 3.0mg/L CPAM, the conversion rate of sulfur could be increased by 11.78%.Under the optimal condition of 1.0mg/L PCF-1, the conversion rate of sulfur and the sulfide removal rate increased by 13.94% and 1.00% respectively, the production of SO42- was decreased by 8.05% compared with ordinary system. Suitable hydraulic conditions, segregation pattern and enhanced flocculation technology could guarantee the sulfur particles were separated effectively. Under the same conditions, the effect of centrifugal separation was best, under the condition of the separation factors for 1558 after 10min, the turbidity removal rates of flocculation system and ordinary system were 99.46% and 98.56% respectively.The result of X-Ray Diffraction indicated that the solid phase products of flocculation system and ordinary system were constitutionally stable Sg at room temperature. The result of particle size distribution fitting of the sulfur floes and fluorescence microscopy indicated that the data of particle distribution was fitted by Gamma equation, the growth model of sulfur floes conformed to the Sutherland Group Aggregation, which the sulfur floe formation process was a process dominated by Cluster-Cluster flocculation. The results of SEM and fractal dimension of the sulfur floes indicated that the flocculation strengthening mechanism of PCF-1 was mainly by changing the system of Zeta potential and adsorbing the negatively charged sulfur with long molecular chains of PCF-1, which could prompted the sulfur particles of newly generated at a faster rate grows into a medium floes, at the same time, the floes porosity of sulfur could reduced and the degree of dense floes could enhanced. Therefore the stability of the sulfur was improved and reduced the surface area of contact with the oxidant, and ultimately controlled the occurrence of side reactions effectively, achieved the purposes of strengthening controlled oxidation of sulfur-containing wastewater.