The vigorous development of China's architectural ceramics industry, the continuous increase of ceramic enterprises, and the environmental protection issues of ceramic enterprises have increasingly become prominent issues. In 2004, the ceramic companies must focus on the treatment of ceramic wastewater. The composition of ceramic waste water is related to the production process and the characteristics of the production products. The pollution factor and water quality index are basically the same. Through the detection of waste water from the ceramic companies, it was found that the most important pollution factor of ceramic waste water is suspended solids. Therefore, to a certain extent, it can be said that the treatment of ceramic wastewater is mainly the treatment of high suspended solids and high turbidity water.
Domestic research institutes have used chitosan flocculation to clean ceramic wastewater and achieved good results. Through experiments, the optimal flocculation conditions of chitosan were found out.
Take ceramic waste water separately, adjust its PH value, add a certain amount of chitosan solution, stir and settle. The test results show that chitosan exhibits good flocculation performance when the pH of ceramic wastewater is ≤8. Further experiments show that the optimal pH range for treating ceramic wastewater is between 4-7.
Separately take the same amount of ceramic wastewater, adjust the pH, add different concentrations of chitosan, static precipitation. The light transmittance of the supernatant was measured. The results showed that when the concentration of chitosan was about 0.1 mg/L, the flocculation effect was the best. Through comparison with the most commonly used inorganic flocculant aluminum sulfate, the treatment of the same wastewater required aluminum sulfate 100 mg/L, aluminum salt The optimal pH for flocculation is 6-7.
The mechanism of chitosan flocculation cleaning ceramic wastewater is that the cations of chitosan can simultaneously exert electric neutralization, agglomeration and the effect of flocculation of bridging and bridging. In other words, the cationic active group on the polymer chain is attracted to the negatively charged ion (SiO32-), which reduces and neutralizes the surface charge of the colloidal particles, and also compresses the colloidal particle diffusion layer to coagulate the colloidal particles. And with the aid of polymer chain bridging and flocculation and sedimentation. In addition, chitosan also has the effect of flocculating heavy metal ions, which can effectively reduce the concentration of heavy metal ions in ceramic wastewater.
Chitosan is rich in sources and belongs to the second largest renewable resource on the earth. It is non-toxic and tasteless, can be fully biodegraded, and participates in the carbon and nitrogen cycle of the ecosystem. It has broad application prospects in the environmental protection of ceramics.