Abstract: Provided is a method for preparing fly ash-based layered double hydroxides (LDHs) modified by molybdenum sulfide intercalation. The fly ash-based LDHs are prepared by mixing washed fly ash with AlCl3 and hydrochloric acid and adjusting pH by using NaOH. On this basis, a single-phase material, molybdenum sulfide intercalation-modified fly ash-based LDHs, is prepared by coupling MoS42? via a mechanochemical process. The process can not only significantly improve the adsorption capacity of the fly ash-derived LDHs for heavy metal ions including Pb2+, Ag+, Hg2+, and Cu2+, but also endow the LDHs with heavy metal adsorption selectivity, with the following order: Ag+>Hg2+>Cu2+>Pb2+>others. In addition, the mechanochemical process can remarkably reduce Mo leaching, thereby lowering material hazard while also reducing cost, energy consumption, and environmental impact.

Abstract: Provided is a system and a method for low-temperature treatment of heavy metals and dioxins in fly ash. In the present disclosure, the fly ash is subjected to tertiary water washing and then separation by pressure filtration with a plate and frame filter press to obtain fly ash after the tertiary water washing. A low-temperature heat treatment is conducted on the fly ash after the tertiary water washing in a stirring reactor by adding an additive combination. Chlorine salts in the fly ash can be effectively removed by the tertiary water washing, which avoids the chlorination of a precursor in the fly ash to form dioxins during the low-temperature pyrolysis, thereby improving a heat reduction efficiency of the dioxins in the fly ash. Moreover, the reduction of a chlorine content in the fly ash can also avoid deactivation of the additives and improve a solidification effect of the heavy metals.

Abstract: A method for preparing zeolite based on waste incineration fly ash is provided, including: step (a) subjecting the waste incineration fly ash to acid washing to remove impurities, followed by water washing and drying; and step (b) adding a mixture of FeCl3 and FeSO4 to washed and dried waste incineration fly ash, followed by mixing with a alkaline solution, putting into a ball milling tank together with grinding balls for a mechanical chemical reaction, and heating reaction materials in a process of ball milling to obtain the zeolite. The method employs acid washing to effectively remove most impurities from the waste incineration fly ash, significantly enhancing a ratio of silicon to aluminum, thus improving the purity of the synthesized zeolite.

Abstract: A method for preparing zeolite based on waste incineration fly ash is provided, including: step (a) subjecting the waste incineration fly ash to acid washing to remove impurities, followed by water washing and drying; and step (b) adding a mixture of FeCl3 and FeSO4 to washed and dried waste incineration fly ash, followed by mixing with a alkaline solution, putting into a ball milling tank together with grinding balls for a mechanical chemical reaction, and heating reaction materials in a process of ball milling to obtain the zeolite; a mass ratio of FeSO4 to FeCl3 in the mixture being 5.5:1 and a mass ratio of the washed and dried waste incineration fly ash to the mixture being (5-10):1. The method employs acid washing to effectively remove most impurities from the waste incineration fly ash, significantly enhancing a ratio of silicon to aluminum, thus improving the purity of the synthesized zeolite.

Abstract: A method for preparing zeolite based on waste incineration fly ash is provided, including: step (a) subjecting the waste incineration fly ash to acid washing to remove impurities, followed by water washing and drying; and step (b) adding a mixture of FeCl3 and FeSO4 to washed and dried waste incineration fly ash, followed by mixing with a alkaline solution, putting into a ball milling tank together with grinding balls for a mechanical chemical reaction, and heating reaction materials in a process of ball milling to obtain the zeolite; a mass ratio of FeSO4 to FeCl3 in the mixture being 5.5:1 and a mass ratio of the washed and dried waste incineration fly ash to the mixture being (5-10):1. The method employs acid washing to effectively remove most impurities from the waste incineration fly ash, significantly enhancing a ratio of silicon to aluminum, thus improving the purity of the synthesized zeolite.

Abstract: A catalytic oxidation system for efficient conversion and removal of volatile organic compounds (VOCs) in a coal chemical industry is provided. The catalytic oxidation system includes a reactor and a first temperature control system, where the reactor is provided with a waste gas inlet and a waste gas outlet and is provided with a preheating zone, a reaction zone, and a heat recovery zone sequentially in a flow direction of a waste gas, and a catalyst is filled in the reaction zone; and the first temperature control system includes a first serpentine pipe buried in the catalyst and a first steam drum arranged outside the reactor, the first steam drum and the first serpentine pipe are connected through a pipeline to form a circulation line, and a temperature in the reaction zone is adjusted to 150° C. to 350° C. by controlling a pressure of the first steam drum.

Abstract: Provided is a system and a method for low-temperature treatment of heavy metals and dioxins in fly ash. In the present disclosure, the fly ash is subjected to tertiary water washing and then separation by pressure filtration with a plate and frame filter press to obtain fly ash after the tertiary water washing. A low-temperature heat treatment is conducted on the fly ash after the tertiary water washing in a stirring reactor by adding an additive combination. Chlorine salts in the fly ash can be effectively removed by the tertiary water washing, which avoids the chlorination of a precursor in the fly ash to form dioxins during the low-temperature pyrolysis, thereby improving a heat reduction efficiency of the dioxins in the fly ash. Moreover, the reduction of a chlorine content in the fly ash can also avoid deactivation of the additives and improve a solidification effect of the heavy metals.