| dc.description.abstract | Abstract
Due to energy shortage nowadays, the characteristics of the low power consumption is highly regarded. Photonics products and photonics industries are fast growing. Solar battery becomes hot in spite it was long-term in low demanding. LED keeps popular and is broadly applied to the telecommunication, information, biochemistry, medical, industry, consuming, astro-technology and military.
By the advantage of high electron mobility and high stability, the Gallium Arsenide is a potential substance to replace the silicide component and become the major component in photonics material. Because AsH3 is the major material to make the Epitaxy wafer, the Arsenic-Containing Wastewater and Rejection will contaminate the circumstance severely. The more growth of the Photonics industry, the more severe populations shall be processed.
Generally, it is the major solution to add Calcium salt or Sodium Salt into arsenic-containing wastewater. Calcium Chloride is popular because of its cheap. However, Arsenide is always to be released out due to the PH-value fluctuation, and even after processed the effluent water cannot comply with the regulated limit, less than 0.5mg/L. This is the biggest problem to process the arsenic wastewater of the photonics industry.
I take one photonics factory as the case and try to objectify my investigation into two subjects. 1.: How many effects can be promoted basing on the engineering betterment and the process tuning to the procedures of a wastewater factory. 2.: With respect to different concentrations, the wastewaters are processed by the Chemical Coagulation. We try to optimize the mixing ratios between Ferric Chloride and Calcium Chloride and the quantities of phase adding between Ferric Chloride, Calcium Chloride and PAC, so that the removbility of arsenic in wastewater can be derived. The next steps are to analyze the arsenic remaining in the sludge and further modify the obtained optimization, and we try to balance the lowest addition dosage to arsenic wastewater and the validity of regulations in effluent water.
Resulting from my experiment, I find the Ferric Chloride is the best one among three coagulators, better than Calcium Chloride and PAC. For high concentration arsenic wastewater, by adding 7 mg/L of Ferric Chloride into wastewater, 99.9959% arsenic can be removed away that is only 0.00336 mg/L be remained in wastewater.
To study the arsenic removiblity to the low concentration arsenic wastewater, we compare three coagulators, Ferric Chloride, Calcium Chloride and PAC, by adding them into wastewater phasingly. We find if Calcium and Ferric are added in the ratio of (0.68/1.4) mg/L, 92.3569% arsenic can be removed from wastewater that is only 0.05147 mg/L be remained in wastewater.
Keywords:
Photonics Industry、LED、Arsenic-Containing Wastewater、Chemical Coagulation | en_US |