Research On Treatment Of Phosphorus Wastewater By Calcium Sulfate And Its Mechanism Discussion

In recent years, industrial by-products have been used as adsorbents for the removal of phosphate from wastewater.In the study,calcium sulfate was taken for trial. Micron-Calcium Sulfate whisker and nano-Calcium Sulfate were synthesized firstly. The ZWP-A,CTAB,temperature were investigated in the hydrothermal method. Nano-calcium sulfate was Synthesized by emulsion menthod. Raw material concentration, silane coupling agent KH550, temperature, ultrasonic, mixing intensity which were accounted as the mainly factors in the Synthesis were discussed in the exeperiment. It is showed that diameter 50 100nm calcium sulfate nano-tube could be synthesized when Na₂SO₄ and CaCl₂ concentration was 0.10mol/L, the concentration of CTAB was 1.8mmol/L, the concentration of KH550 was 0.027mol/L under 700r/min stirring speed and 1h ultrasonic .Industrial grade calcium sulfate, micron -calcium sulfate whisker, nano- Calcium sulfate were applied for Phosphorus Removal trial. The different effects were investigated.The results showed that removal rate of Industrial grade calcium sulfate stabilize at 80% in 1h ,and the micron -calcium sulfate whisker, nano-Calcium sulfate apparently had a higher Efficiency.The removal rate was more than 90% in 15min Operating time , and drainage comply with the national standard. Generally ,advantageous process parameters for phosphorus removal was below:alkaline waste water (pH> 10), the lower phosphorus concentration (<20mg/L), dosage of 0.5⁰.8g/L.Linear fit of thermodynamics and kinetics equation was applied for the phosphorus removal mechanism discuss on the base of experiment.The results showed that D-R isothermal equation suited to describe three kinds of different size range of industrial-grade calcium sulfate with higher Linear correlation.Factually,the dynamic process was so complex, the results showed the particle size has a greater impact through the proess. Removal process of Micron-calcium sulfate whisker is in line with the characteristics of ideal chemical adsorption. Langmuir equation, Temkin equation has a high degree of linear correlation above 0.99, Kinetic fitting results showed that quasi-second kinetic equation fit to the proess. Removal process of Nano-calcium sulfate is in line with Temkin isothermal equation, and the most appropriate kinetic equation subject to second-order reaction kinetic equation.