The calcium arsenate waste, containing amounts of arsenic (7.62 wt%), was treated using solidification/stabilization technology (S/S) with geopolymer. In order to optimize the procedure for S/S, 9 different S/S samples, differing in amount of the geopolymer materials were prepared. On these samples, extraction tests were performed, showing that the arsenic concentration in the leachate was less than the China countermeasure standard (5 mg/l) after 28 days of curing when a geopolymer (GP) dosages more than 30 wt%. Furthermore, the samples showed substantially decreasing leachability with curing times. But there was no appreciable change in leachability under various time and pH conditions.
The sodalite was prepared with metakaolin by the ionothermal method in deep eutectic solvent(choline chloride/urea). Such factors as the Na2O/SiO2 ratio, crystallization temperature and time had effects on the structure and property. The high crystallinity and purity of sodalite can be obtained at the Na2O/SiO2 ratio of 3:1, and the temperature of 180°C for 60h. The product was characterized by means of X-ray diffraction, Infrared spectrum and scanning electron microscopy.
The accumulation of industrial waste residues is a serious problem with the continuous development of industrial productions during the recent years, how to use reasonably the industrial waste residues has gradually turned into an important research field in the world. Therefore, the research and development of porous ceramics synthesized by the industrial waste residues of fly ash, coal gangue and red mud etc as the raw materials were introduced, the present preparation technique and characteristics of the porous ceramics synthesized by the industrial waste residues were analyzed, and its further investigation was discussed.
Pilot scale tests are conducted to study the pre-ozonation effect of the micro-polluted surface water and its influence on the operation and treatment effects of the follow-up filtration units. The results showed that significant improvement of sand filtration performance was achieved through the use of ozone pretreatment, and the filtration cycle was nearly doubled. The THMFP removal rates of the pre-ozonation technology and the conventional technology are respectively 32% and 18%, and the former one has reduced obviously the particle number of sand filtration effluents which implied the reduced probability of detection rates of effluent microorganisms and pathogens. Long-term run effect showed that the pre-ozonation process was superior to conventional processes in CODMn and turbidity removal.
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