Study On Resource Utilization And Treatment Process Of Triphenylphosphine Wastewater

A series processes of micro-pore preaeration, distill, deposition, coagulate, Fenton reagent oxidation, activated carbon adsorption were developed to treat riphenylphosphine wastewater. The principle, characteristic, effect factors were investigated through detecting and analyzing. The optimum parameters were obtained after analyzing reaction mechanisms of each process. Wastewater treatment scheme was designed in the last. The results were summarized as follows:(1) Aeration time had appreciable effect on the removal of turbidity, chroma, COD, methanol and toluene. Aeration intensity also had obvious effect on the removal of COD, methanol and toluene, but had few effects on the removal of turbidity and chroma. The optimal aeration intensity and aeration time for methanol were 6L/min and 4 hours, increasing aeration intensity and prolonging aeration time performed few effects on the removal rate of methanol, while for toluene the optimum aeration intensity and aeration time were 8L/min and 2 hours.(2) From the comparison test of different holding temperature and holding time, the results showed that the optimum holding temperature and holding time were 90℃and 180min respectively. Under these conditions, the concentration of COD decreased from 21280mg/L to 12962mg/L and methanol from 11125mg/L to 2223mg/L. However, the optimum holding temperature for toluene was 70～80℃.(3) The concentration of Calcium and Magnesium Ions can be decreased from 71714 mg/L to 1738 mg/L when alkies were added to keep pH at 8.5. The purity of magnesium hydroxide in the recovery deposit was 89.7%. Meanwhile, the concentration of COD, methanol and toluene were decreased from 12000mg/L, 2223mg/L and 375mg/L to 3000mg/L, 1542mg/L and 165mg/L, respectively. Coagulation process could further increase the removal efficiency of COD. Under the optimized process conditions( PAC 30mg/L, pH 8.5, PAM 4 mg/L), the maximum removal rate of COD was 51.4%, and the concentrations of toluene and methanol decreased to 13.5mg/L and 892mg/L.(4)The results of orthogonal test showed that the most important parameter for Fenton reagent oxidation was the dosage of H2O2, successively followed with the dosage of FeSO4·7H2O, pH and reaction time. The results of single factor experiment showed that the optimum conditions for Fenton reagent oxidation were H2O2 8ml/L, FeSO4·7H2O 1.5g/L, pH3, reaction time 120min and dosage for three times. Under optimal conditions, the concentrations of COD, methanol and toluene were 450.5 mg/L, 140mg/L , and 3.7mg/L, and the removal efficiency were 75.3%, 84% and 72.6%, respectively.(5) The active carbon adsorption experiment played an important role in removing organic compounds. For the oxidized riphenylphosphine wastewater, the results of dosing and timing test showed that the optimum dosage and adsorption time for active carbon adsorption were 40mg/L and 30 min. Under this condition, the concentrations of COD, methanol, and toluene in the effluent were 367.5mg/L, 82.5mg/L and 0.8mg/L, respectively.