Search

Integrated circuit industry is a strategic, fundamental and pilot industry that supports economic and social development. It has high water consumption and drainage. The quality characteristics of integrated circuit wastewaters were classified, including ammonia wastewater, fluorine wastewater, acid and alkali wastewater, organic wastewater, copper wastewater, and grinding wastewater. The treatment processes and technologies of up-to-standard discharge, pollutant resource recovery, and water reuse treatment of wastewater containing different pollutants were summarized. The physicochemical processes for up-to-standard discharge treatment included coagulation sedimentation, filtration and adsorption to treat fluorine-containing, copper-containing and grinding wastewater, and biochemical processes included hydrolytic acidification, internal circulation anaerobic reactor, AO, and membrane bioreactor to treat ammonia-containing and organic wastewater. Advanced oxidation and electrolysis technology received much attention in recent years. The resource recovery technologies for pollutants such as fluorine, copper and tetramethylammonium hydroxide in wastewater included ultrafiltration and electrodialysis. Wastewater reuse treatment technologies and processes included coagulation sedimentation, membrane bioreactor and filtration. Reverse osmosis was the core of wastewater reuse treatment, with the goal of producing industrial pure water for integrated circuit manufacturing. Finally, the problems faced in wastewater treatment were discussed. Corresponding control methods were suggested: improving the collection system, strengthening the removal of heavy metals and refractory organic pollutants to reduce the biological toxicity of wastewater, and using pretreatment, fouling monitoring, membrane cleaning, and developing new membrane materials methods to control reverse osmosis membrane fouling.

Developing nanomaterials with high H2O2‐decomposition capacity to replace traditional biological enzymes is of great importance in environmental, semiconductor, and medical fields. However, a lack of understanding of the reaction mechanism leads to aimless catalyst design and limits further improvement of catalytic activity. Here, the regulatory mechanism based on the electron filling and orbital energies of the metal active centers is demonstrated and a rational catalyst design strategy is provided to achieve ultrahigh H2O2‐decomposition activity. Among the five platinum‐group‐metal active centers investigated in this study, the Ir–N4 with partially occupied dx2−y2 and dxz orbitals and the highest d‐band center most strongly interacts with H2O2, and show the lowest energy barrier for H2O2 decomposition. As expected, the single‐atom Ir catalyst (Ir‐NC) shows an ultrahigh H2O2‐decomposition capacity, which is 1614‐times higher than that of natural catalase. Surface‐adsorbed atomic oxygen is observed and verified to be the key intermediate for O2 generation. Biocompatible Ir‐NC is effective in scavenging intracellular reactive oxygen species and holds great potential for clinical therapeutics associated with oxidative stress. This study advances the mechanistic understanding of H2O2 decomposition and provides useful guidance for rational design of high‐performance artificial nanozymes. [ABSTRACT FROM AUTHOR]

Developing advanced bifunctional water splitting electrodes that can perform both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is critically important for sustainable hydrogen production because of the simplicity in implementing the system where only one type of electrode material is required. However, the cell voltage of currently available electrolyzers using bifunctional electrodes is still high because maintaining high intrinsic OER and HER activity simultaneously while keeping good charge and mass transport is a challenging task. Herein, the dense ternary NiMoFe alloy nanoparticles are in situ precipitated on the highly conductive hierarchical MoO2 nano-pillar arrays (NiMoFe NPs@MoO2 NPAs) to form an ultra-hydrophilic and super-aerophobic structure by the reductive annealing process-induced phase separation method. Benefiting from the intrinsically high OER and HER activity, abundant active sites and excellent charge and mass transport, the as-obtained NiMoFe NPs@MoO2 NPAs exhibit ultra-low overpotentials of 79 mV for hydrogen evolution and 246 mV for oxygen evolution at 100 mA cm−2. The assembled two-electrode cell delivers the industrially relevant current densities of 100 and 1000 mA cm−2 at record low cell voltages of 1.52 and 1.66 V while maintaining an almost unchanged potential over 1000 h water splitting. The present method of in situ constructing multielement alloy nanoparticles on hierarchical structure also shows great simplicity and broad applicability potential for preparing high-performance electrocatalysts beyond water splitting. [ABSTRACT FROM AUTHOR]

This study investigated the photocatalytic removal of endocrine-disrupting compounds (EDCs), estrogenic activity, and Escherichia coliform ( E. coli) in secondary effluents from a wastewater treatment plant in a cylindrical photocatalytic reactor. Its application for advanced wastewater treatment processes was evaluated. Estrone, 17α-estradiol, estriol, nonylphenol, and bisphenol A were chosen as target EDCs because of their high prevalence in wastewater. EDCs, estrogenic activity, and E. coli in the secondary effluent were rapidly removed within 100 min of TiO2 photocatalysis. Reactor performance was enhanced significantly by TiO2 photocatalysis compared with UV photolysis. Filtration was evaluated as a pretreatment method in TiO2 photocatalysis by comparing the reduction rate of estrogenic activity and E. coli in filtered samples with unfiltered wastewater samples. The inactivation rate of E. coli increased significantly after filtration, whereas the estrogenic activity reduction rate only slightly increased. This could be attributed to the partial impeding effects of suspended solids on photosensitive reactions induced by humic acid during photocatalysis. TiO2 photocatalysis with filtration pretreatment can be an effective method for advanced wastewater treatment. This is the first report on the removal of EDCs and E. coli from secondary effluents using TiO2 photocatalysis as an advanced wastewater treatment process. [ABSTRACT FROM AUTHOR]

Developing efficient heterogeneous H 2 O 2 decomposition catalysts under neutral conditions is of great importance in many fields such as clinical therapy, sewage treatment, and semiconductor manufacturing but still suffers from low intrinsic activity and ambiguous mechanism understanding. Herein, we constructed activated carbon supported with an Ir-Fe dual-metal-atom active sites catalyst (IrFe-AC) by using a facile method based on a pulsed laser. The electron redistribution in Ir-Fe dual-metal-atom active sites leads to the formation of double reductive metal active sites, which can strengthen the metal-H 2 O 2 interaction and boost the H 2 O 2 decomposition performance of Ir-Fe dual-metal-atom active sites. Ir-Fe dual-metal-atom active sites show a high second-order reaction rate constant of 3.53 × 10 6 M -1 ·min -1 , which is ∼10 6 times higher than that of Fe 3 O 4 . IrFe-AC is effective in removing excess intracellular reactive oxygen species, protecting DNA, and reducing inflammation under oxidative stress, indicating its therapeutic potential against oxidative stress-related diseases. This study could advance the mechanism understanding of H 2 O 2 decomposition by heterogeneous catalysts and provide guidance for the rational design of high-performance catalysts for H 2 O 2 decomposition.

Urban wastewater treatment plant (WWTP) effluent as reclaimed water provides an alternative water resource for urban rivers and effluent will pose a significant influence on the water quality of rivers. The objective of this study was to investigate the spatial and temporal variations of water quality in XZ River, an artificial urban river in Shenzhen city, Guangdong Province, China, after receiving reclaimed water from WWTP effluent. The water samples were collected monthly at different sites of XZ River from April 2013 to September 2014. Multivariate statistical techniques and a box-plot were used to assess the variations of water quality and to identify the main pollution factor. The results showed the input of WWTP effluent could effectively increase dissolved oxygen, decrease turbidity, phosphorus load and organic pollution load of XZ River. However, total nitrogen and nitrate pollution loads were found to remain at higher levels after receiving reclaimed water, which might aggravate eutrophication status of XZ River. Organic pollution load exhibited the lowest value on the 750 m downstream of XZ River, while turbidity and nutrient load showed the lowest values on the 2,300 m downstream. There was a higher load of nitrogen and phosphorus pollution in the dry season and at the beginning of wet season.