Development Of Chemical Industry Research Articles

Expansion Direction Selection of the Coal-to-Olefin Industrial Chain in Inner Mongolia from the Value Chain Perspective

Inner Mongolia is a key region for China’s clean energy production and a demonstration base for modern coal chemical industry production. However, modern coal chemical industry development in this region faces many problems, such as complex downstream product structures, low value-added products, and severe environmental pollution. With limited future coal allowance in the coal chemical industry, the scarce available coal will likely be allocated to fields with strong product competitiveness to enhance industrial chain value. Given this, the Inner Mongolia coal-to-olefin industrial chain is selected to explore its strategic expansion directions. An improved value chain accounting method is proposed to account for the value of each segment of the coal-to-olefin industrial chain in Inner Mongolia from 2011 to 2022. The improved value chain accounting method is then combined with system dynamics to construct a model for selecting the expansion directions of the coal-to-olefin industrial chain based on the value chain perspective. Finally, the differences in the value of each future expansion direction are analyzed through scenario simulation and comparison. The most important result is that the higher the extension of the coal-to-olefin industry chain in Inner Mongolia, the higher the value of the industry chain. Carbon punishment is the most important factor affecting the value of the industry chain, and enterprises and governments should increase investment in innovation and renewable energy. Accordingly, this study provides a decision-making method for selecting the optimal expansion direction of the modern coal chemical industrial chain in Inner Mongolia.

Effect of different water reducing agents on mechanical properties and micro-mechanism of modified hemihydrate phosphogypsum cementitious materials

The stockpiling of industrial by-product phosphogypsum causes pollution to the environment, and its effective utilization can be achieved by using cementitious materials from undisturbed hemihydrate phosphogypsum (UHPG) obtained by hemihydrate-wet process. This study investigated the creation of modified hemihydrate phosphogypsum mixture by proportionally blending quicklime with UHPG. Modified hemihydrate phosphogypsum cementitious material (MPGCM) was then prepared using melamine superplasticizer (SM) or naphthalene superplasticizer (FDN). The effects of these water reducing agents on the mechanical properties and micro-mechanisms of MPGCM were evaluated by single-factor experimental method. The results showed that both SM and FDN were effective in reducing water consumption and enhancing the fluidity of MPGCM. Additionally, both superplasticizers delayed the establishment of the MPGCM, with FDN showing a stronger retarding effect than SM. Compared with those mixed with FDN, the specimens mixed with SM exhibited markedly greater flexural and compressive strengths. The specimens with 2 % SM content achieved the highest 28 d flexural strength and compressive strength, measuring 16.61 MPa and 42.26 MPa. Microscopic analysis revealed that the water reducing agent can not only inhibit the disaggregation and dissolution of calcium sulfate hemihydrate and the crystallization of calcium sulfate dihydrate, but also promote the transformation of calcium sulfate dihydrate crystals from long rods to short columns or plates, so that the reticular structure is more compact and the mechanical strength is improved. This study suggests that the optimal composition, consisting of 97 % UHPG, 3 % quicklime, and 2 % SM, yields the optimum mechanical properties. These results provide a theoretical foundation for the application of phosphogypsum in practical engineering and support the sustainable development of phosphorus chemical industries.

Study of the structure guide mechanism of solid phase synthesis of CAN zeolite from coal gasification slag and its fixation of the Cr6+ structure in wastewater

The generation of a large amount of coal gasification coarse slag (CGCS) restricts the sustainable development of the modern coal chemical industry. This paper uses CGCS as raw material, adopts a solid phase synthesis method, saves water resources, is a new method of synthesizing zeolite with low secondary pollution. Different types of anions were used to induce the synthesis of zeolites. Using XRD, FT-IR, 27Al-NMR, 29Si-NMR, BET, SEM, and experimental research methods, the activation and depolymerization of CGCS in the solid phase reaction and the guiding role of anions in crystal growth were studied. The results revealed that the anionic structure with triple rotational axis symmetry can induce the synthesis of single-phase CAN zeolite. Using this rule, CAN zeolite was synthesized using CGCS as raw material and Cr6+ containing wastewater with triple rotation axis symmetry as the structural guide agent, and Cr6+ in wastewater was structurally fixed. Compared to the adsorption effect of CGCS on Cr6+, the results showed that the synthesized CAN zeolite was found to effectively fix Cr6+ (74.98 mg/g) from wastewater, which was much higher than that of CGCS (24.85 mg/g).

Spectral properties regulation for the performance improvement of solar-driven methane dry reforming reactor based on the photothermal synergistic catalysis

With the development of chemical industry, many chemical reactions are expected to be directly driven by solar energy. Among them, methane dry reforming (MDR) is a highly promising reaction system. Since all the energy required for MDR comes from solar energy, the temperature distribution and reaction characteristics in the reactor are determined by radiation transportation, and therefore regulating the optical properties according to the spectral distribution characteristics becomes necessary for improving the chemical conversion performance of the reactor. In this paper, aiming at the specific strengthening mechanism of different spectra in photothermal synergistic catalysis, the spectral response characteristics in the reactor were purposefully regulated, so as to achieve the improvement of reactor efficiency and reaction conversion performance. By adjusting the optical properties of compound parabolic concentrator (CPC) and porous catalytic absorber (PCA) in a cavity reactor, the CO2 conversion can be increased by 68.52%, the CH4 conversion can be increased by 54.48%, and the solar-fuel efficiency can be increased to 6.16%. This indicates that the selectivity of different bands of full spectrum can significantly affect the reactor performance. Through the above research, this paper aims to provide a new optimization idea for the photothermal reactor.

Coupled Spatial–Temporal Evolution and Influencing Factors of Chemical Industry Development and Water Environment in Yangtze River Economic Belt

Revealing the coordinated correlation between chemical industry development and the water environment is essential for promoting high-quality development in the Yangtze River Economic Belt. Based on the data in the Yangtze River Economic Belt from 2011 to 2021, this study explores the spatial–temporal evolution and influencing factors of the coupled coordination between chemical industry development and the water environment by using the global entropy method, a coupling coordination model, and the Tobit model. The results indicate a general upward trend in the comprehensive indices of chemical industry development and water environment systems, albeit with distinct spatial patterns. A mismatch between the two systems is observed in terms of spatial distribution. Regarding the coupling coordination degree, the relationship shows an upward trend, primarily at a mild-to-moderate coupling stage, exhibiting a spatial pattern of “downstream > midstream > upstream”. Moreover, a trend of increasing coordination and narrowing disparities between high- and low-level regions can be observed. The model results suggest that environmental regulation, economic development, government capacity, and urbanization play a crucial role in promoting the coupled development of the chemical industry and the water environment. However, openness to external markets may not enhance coupled coordination. These findings may provide policy guidance for the development status of two subsystems in other locations.

Synergistic effect of inner filtering effect and host-guest interaction based on β-cyclodextrin fluorophore for promoted 4-nitrophenol detection

Efficient detection of 4- nitrophenol (4-NP) organic pollutant is always a very important issue due to the rapid development of chemical industry and the abuse of pesticides and so on. Here, we designed and synthesized a novel supramolecular fluorescent probe, 4-[4-(acetylamino)styryl]-1-cyclodextrin pyridinium p-toluenesulfonate (ASPT-β-CD), for the selective and sensitive detection of 4-NP. The introduction of β-CD not only improves the water solubility of probe and can also be used as a host to encapsulate 4-NP. In alkaline aqueous solution, the absorption spectrum of 4-NP overlaps the excitation spectrum of ASPT-β-CD and suggests that an internal filtration effect occurs between them. We explored the possible response mechanism and speculated that the high selectivity and high sensitivity were derived from the synergistic effect of inner filtering effect and host-guest interaction. Benefiting from the synergistic effect, the proposed sensor ASPT-β-CD displayed significant "turn-off" after adding 4-NP, while showing a fast response to 4-NP within 2 min and low LOD about 0.01 μM. In addition, this method has been successfully applied to the determination of 4-NP in lake water samples, indicating that the obtained ASPT-β-CD has great practical application potential in the environmental field.

Evolution and Optimization Simulation of Coastal Chemical Industry Layout: A Case Study of Jiangsu Province, China

In the face of geopolitical challenges and climate change, economic progress, safe production, and environmental protection have emerged as important directions for chemical industry development. However, the rational optimization of the chemical industry layout under the backdrop of ecological environmental protection necessitates further exploration. This study explores the evolution and future development direction of the chemical industry layout within the coastal region of Jiangsu Province, China, using the CA–Markov model. The findings reveal a trend of spatial agglomeration growth among coastal chemical enterprises, with Moran’s Index increasing from 0.109 in 2007 to 0.206 in 2017. The petrochemical industry, in particular, demonstrated the most significant agglomeration effect, with approximately 52.10% being concentrated in 14 coastal industrial parks in 2017. Under the constraints of the ecological environment and policy guidance, the land area allocated for the chemical industry experienced a reduction of over 10%, further strengthening the emphasis on spatial agglomeration. Chemical industries along Jiangsu’s coast have become agglomerated and concentrated near industrial parks and ports. Their spatial distribution and connectivity were mainly influenced by factors such as convenient transportation, the ecological environment, local policies, the distance from residential areas, and industrial agglomeration. Under different scenarios—including natural growth, ecological environment constraints, and policy guidance—chemical industries show diverse spatial patterns. Ecological environmental constraints and policy guidance can provide various intervention methods for the government to promote the optimization direction and focus of the chemical industry layout while minimizing its impact on the ecological environment.

Production of jet fuel cycloalkanes from 5‐(hydroxymethyl)furfural via cascade catalysis on Mg(Al)(Zr)O supported CuCo

AbstractCatalytic conversion of biomass‐derived 5‐(hydroxymethyl)furfural (5‐HMF) into carbon‐increased hydrocarbons as drop‐in energy‐rich biofuels has received a great deal of concern for the development of sustainable chemical industry. Here, we demonstrate a one‐pot conversion of 5‐HMF into C9‐alkanes on one single catalyst, acidic–basic layered double oxides (Mg(Al)(Zr)O) supported CuCo alloy. The well‐defined multifunctional catalytic sites with harmonious combination carry out cascade catalysis, affording C9‐alkanes (including 30% of more value‐added branched‐cycloalkanes) in 83% yield. The basic–acidic sites on Mg(Al)(Zr)O show high activity for aldol condensation of 5‐HMF and acetone, producing 4‐[5‐(hydroxymethyl)‐2‐furanyl]‐3‐buten‐2‐one (HAc) in a yield of >99%. The engineered Co–Cu–Co linkages on supported CuCo perform efficient hydrodeoxygenation, affording C9‐alkanes in a selectivity of 96% from HAc. C9‐cycloalkanes are generated from the cyclization of the corresponding monohydric alcohol intermediates by the synergy of acidic and CuCo sites in the hydrodeoxygenation reaction.

Rice husk-based biogenic silica-anchored Sn-Co bimetallic catalysts for cellulose hydrogenolysis: Structural regulation and mechanism study

The production of high value-added chemicals and materials from renewable biomass is significant for the sustainable development of chemical industry. Herein, rice husk-based biogenic silica-anchored Sn-Co catalysts with adjustable activity are successfully prepared for biomass valorization. By regulating the pretreatment method and carbothermal reduction temperature of catalysts, the interaction between Co, Sn and biogenic silica can be regulated, thereby regulating the catalytic activity of the catalyst for cellulose hydrogenolysis. 50.7 % yield of acetol and 63.4 % yield of C3 products can be obtained. A series of characterizations show that the hydrothermal pretreatment in CoCl2 solution promotes the combination of Co2+ and biogenic silica, which inhibits the excessive doping of Sn4+ and promotes the formation of Co3Sn2 alloy. The Sn-O-Si and Co3Sn2 species in 3Sn-5Co@RHC are the key active sites catalyzing glucose isomerization and fructose retro-aldol condensation. The intermediates experiments show that controlling the hydrolysis rate of cellulose to avoid excessive concentration of monosaccharide intermediates in the reaction system is crucial for inhibiting side reactions and improving the yield of acetol. The use of agroforestry waste-based catalytic materials for biomass conversion in this work can provide inspiration for exploiting the intrinsic characteristics of biomass to develop high value-added materials and chemicals.

Development of the Russian chemical complex in 2022

The article presents the results of an analysis of the socio-economic status of the chemical complex in Russia conducted by the authors based on the results of 2022, including the dynamics in the industry of the number of large, medium, and small enterprises, total employment, average capacity utilization, and average wages of chemical industry workers. It is shown that due to the current geopolitical situation, several Russian chemical productions are experiencing difficulties in production and product implementation. The actual number of enterprises in the chemical industry has decreased compared to the beginning of 2022 due to a reduction in the number of small and foreign enterprises in the industry, which is not critical on a national scale in the absence of crisis situations in product implementation. However, the average capacity utilization for major types of chemical products has decreased slightly and currently stands at 70%. The analysis results demonstrate the stability of the employee count and wages. Wages remain at the level of salaries in the manufacturing sector. The conclusion is drawn that the previously identified positive trend in the implementation of the Chemical Industry Development Program until 2030 (Strategy 2030) remains intact, according to the authors.

Functional Catalyst Molecular Sieves in Green Chemical Applications

With the development of green chemical industry and the continuous improvement of environmental awareness, the application of various catalysts in environmental protection has been widely concerned. As a green catalyst, molecular sieve catalyst has superior environmental performance, which is mainly reflected in its ability to improve the selectivity of reaction products, can be reused, good thermal stability and strong adaptability. This paper mainly introduces the types, development history, synthesis technology and application of zeolite catalysts, due to the development of science and technology, a large number of new synthetic zeolite catalysts are used in the field of catalysis and meet the requirements of green chemistry, and its synthesis technology is gradually trending towards environmental protection with the development of green chemistry. Zeolite catalysts are widely used in chemical industry and other fields, and their green environmental protection performance promotes the development of chemical processes in the direction of green chemicals.

Characteristics of air pollution complex in a typical chemical industrial development zone in eastern China

VOCs (volatile organic compounds) have an important impact on the atmospheric environment, climate and human health. In a typical chemical industrial development zone in eastern China, 123 kinds of VOCs were on-line monitored simultaneously at three sites using the GC-FID/MS system for one year. The seasonal and diurnal variations of composition and concentration of VOCs were compared and analyzed systematically. The VOCs features existed significant differences at the three sites, which were greatly affected by the types and emissions of surrounding enterprises. The alkanes appeared as the major pollutants at the site adjacent to petrochemical processing enterprises (site A), while OVOCs were the majority at the other two sites, which were around by the fine chemical enterprises (site B and C). The TVOC concentrations presented seasonal differences at the three sites, which showed higher values in summer (468.6 μg/m3) at site A, in winter (409.2 μg/m3) at site B，and in autumn (298.9 μg/m3) at site C, respectively. The isopentane (16.8%) and ethylene oxide (17.9%) made up the largest proportion of the VOCs at site A and B, respectively. While it was more susceptible to the effects of dichloromethane, 1,2-dichloroethane and chloromethane at site C. Three pollution events of ethylene oxide, isopentane and dichloromethane were analyzed and traced based on the prevailing wind and the change of concentration at the three sites. Further analysis of the impact of VOCs on the formation of secondary pollutants of O3 and PM2.5 found that the contribution of local O3 (28.1 %) in summer was significantly larger in the study area than that in non-industrial area. The multiphase chemical reactions were more likely to occur in autumn, which promoted the formation of secondary PM2.5, showing the correlation coefficient of 0.73 between the secondary organic aerosol formation potential of VOCs and PM2.5.

Nanometer lanthanum hydroxide modified anionic polymer for deep fluoride removal: Adsorption properties and mechanism study

The development of chemical industry has brought about serious fluoride pollution, and there is an urgent need to develop an adsorbent with high efficiency and stability for fluoride removal. Despite the remarkable adsorption capacity of lanthanum hydroxide hydrate for fluoride ions, its industrial application is limited by powder leaching and strict pH requirements.In this study, lanthanum-containing anionic resin (HLO-D201) was synthesized by the method of precursor introduction and in-situ deposition, mainly by introducing La3+ into the resin, adding sodium hydroxide to precipitate it in the resin pore, forming hydrated lanthanum oxide.The characterization analysis showed that hydrated lanthanum oxide (HLO) was successfully introduced into the porous matrix of the resin and existed in the form of crystalline hydrated oxide.Static adsorption experiments demonstrated that HLO-D201 could effectively adsorb fluoride ions in a wide pH range (2–10). Since nano La (OH) 3 was encapsulated in the resin pore, the loss of La (OH) 3 was greatly reduced, and under the condition of competitive adsorption of several coexisting ions, Only phosphoric acid group interferes obviously with the adsorption of F-. The synthesized HLO-D201 still showed good adsorption capacity after regenerated by NaOH–NaCl composite solution for six times. The removal mechanism of fluoride by HLO-D201 is mainly electrostatic attraction and ligand exchange.Overall, HLO-D201 is a kind of fluorine removal adsorbent with excellent performance and wide application prospects.

Substantiation of industry priorities for import substitution of technologies and products (the polymer industry case)

Subject. The article considers the results and prospects for implementation of import substitution policy in the polymer industry. Objectives. The purpose is to develop conceptual provisions for implementation of import substitution policy in the polymer industry, based on the process periodization and imported product evaluation. Methods. The first stage of the study rests on methods of content analysis and periodization to feature the characteristics and form a vision of main stages of the import substitution policy implementation in Russia. The second stage is associated with adaptation and application of methods of ABC/XYZ analysis and calculation of apparent consumption to study the product lines of polymer imports based on indicators characterizing the structure and dynamics of polymer imports. Results. The paper highlights factors determining the effectiveness of import substitution policy implementation in Russia’s polymer industry in modern conditions. It presents the main stages of the policy implementation, including the vision of future stages in terms of development of competitiveness of domestic technologies and products at the global level. We investigated product lines of polymer imports, defined priority segments, identified criteria and key actions for effective implementation of import substitution policy in Russia. Conclusions. The formulated conceptual provisions may become a guideline in elaboration of strategic and program documents for the chemical industry development, serve as additional justification for investment decisions and government support allocation.

Novel membrane contactor-like bioreactor for selective separation and biodegradation of phenol and ammonium from coal chemical wastewater

The development of coal chemical industry usually generates high-concentrated wastewater containing phenol and ammonium, which requires deep treatment before disposal. Herein, a novel combined process of membrane contactor and bioreactor (MCBR) was established for the efficient treatment of phenol-ammonium wastewater for the first time. When pH was in the range of 8–13, the increase of pH weakened the transmembrane mass transfer of phenol and enhanced the mass transfer of ammonia, owing to their different existing forms at different pH values. At a temperature of 20–30 ℃, the transmembrane mass transfer of phenol and ammonia both increased with temperature increasing. Meanwhile, the established transmembrane mass transfer model reflected the same tendencies of phenol and ammonium recovery rates between experiment and theory. The precise control of concentrations of phenol and ammonium by membrane contactor ensured the safety and effectiveness of subsequent biodegradation process. After biodegradation, the concentrations of phenol and ammonium reduced from 120.1 and 78.9 mg/L to 7.8 and 2.5 mg/L, respectively. The volatile solid content of activated sludge remained relatively constant, while the settling ratio decreased from 39 % to 29 %. Overall, this study established a novel MCBR system for green and cost-effective treatment of high-concentrated coal chemistry wastewater.

Enhancing the Electrochemical Properties and Processing Techniques of Carbon Nanotubes for Bio pharmacological Applications: A Research Perspective

Compared with other biopharmaceutical technologies, carbon nanotubes not only have unique structure, but also have strong electrochemical properties, which occupy an important position in the fields of chemistry, physics, biopharmaceutics and materials science, and have played an active role in promoting the development of biopharmaceutics and chemical industry in China. Carbon nanotubes (CNTs) are mainly used in the field of biopharmacology for the determination of small biological molecules and drug molecules, the determination of dopamine and thrombin, the determination of high concentrations of ascorbic acid, and the detection of drug formulations. Although carbon nanotubes (CNTs) have many advantages in the field of biopharmaceutics, there are certain limitations that limit the scope of application of carbon tubes, which are mainly the following: one is the high cost of the carbon nanotube material itself and the high technical difficulty of its preparation; the other is that the smooth surface of the material is not conducive to the loading of other particles; finally, although the carbon nanotubes are modified with different groups after treatment, the structure of the material itself is damaged. Finally, although carbon nanotubes are modified with different groups after treatment, their own material structure is destroyed, which reduces their conduction performance. Although the above defects can affect the performance of carbon nanotubes, they can be solved by optimizing the structure of carbon nanotubes, enhancing the plastic mechanical properties of carbon nanotubes and corrosion resistance, in order to give full play to the role of carbon nanotubes in the field of biopharmaceuticals. In this regard, the author briefly analyzes the electrochemical properties of carbon nanotubes in biopharmacology and the application of treatment methods based on relevant literature and work experience, hoping to provide reference value for related scholars and researchers.

Development and application of slurry–bed production technology of hydrogen peroxide by anthraquinone auto-oxidation process

This article analyzes the problems existing in the domestic hydrogen peroxide production plant, and introduces slurry-bed production technology developed by SINOPEC from various aspects, including anthraquinone hydrogenation catalysts, slurry-bed hydrogenation reactor, high-throughput filtering, oxidation process intensification, efficient extraction, safe and environmentally friendly working solution regeneration technique. The operation of the pilot plant and industrial production plant shows that the technical indicators of the developed technology are significantly better than those of the traditional technology, with high intrinsic safety and easy to large-scale production. The slurry-bed production technology developed by SINOPEC greatly improves the level of hydrogen peroxide production technology in China and provides raw material guarantee for the development of downstream green chemical industry.

Identification of Russian Clusters Based on the Synthesis of Functional and Spatial Approaches

Introduction. The study continues the approbation of the methodology of cluster identification, developed earlier by the authors and the study of regional industry specialization, within the framework of which the database “Clusters of Russian Regions” was developed. The relevance of the topic is the necessity of the methodology for complex clustering of regions in order to provide further recommendations for the development of industrial sectors. The purpose of the article is to develop and test the methodology for identifying clusters on the territory of Russia based on the synthesis of functional and spatial approaches. Materials and Methods. The analysis of intersectoral relations within the framework of the functional approach consisted in the application of the maximum method, which allows to trace the chain of consumption relative to the main suppliers and main consumers between industries based on the Russian “Input – Output” table of 2016. The spatial approach was implemented by calculating location quotients, determining z-scores, correlation coefficients analysis between clusters’ location quotients to establish regional and interregional links. Results. The results of the article have tested the methods proposed by the authors for the clustering process of regions. The results obtained after applying the methods revealed the localization of the cluster “Chemical Products” in the territories of certain regions of the Russian Federation and its existing significant functional and spatial relationship with the clusters: “Construction”, “Production Equipment” and others. Moreover, it has been determined that the chemical industry has different types of connections: both the functional connection (with the “Metallurgy” cluster) and the presence of spatial communication: interregional (“Construction”), regional (“Production equipment” and others). Therefore, it has been proved that an integrated approach is necessary to identify industrial clusters. Discussion and Conclusion. Considerations of previous studies on regional clustering and our obtained results on the cluster “Chemical products” have confirmed the need to use the complex methodology of regional clustering, which includes the synthesis of functional and spatial approaches, since both approaches separately have their limitations: functional connection does not mean the existence of spatial (analysis of clusters “Chemical products” and “Metallurgy” interconnection) and vice versa. This result will help to comprehensively solve the problem of the chemical industry development in Russia, due to the understanding of the competent placement of enterprises and taking into account the relationship with enterprises of various industries. The materials of the article can be useful both for scientists dealing with the problems of regional economic development, and for governmental bodies whose goals include making managerial decisions in the field of industrial development.

Efficiency of submerged ceramic flat membrane bioreactor in the treatment of coal chemical wastewater

Coal chemical wastewater inhibits the development of the modern coal chemical industry. This study used a submerged ceramic flat membrane bioreactor to treat coal chemical wastewater. By combining the characteristics of high flux and high strength of ceramic flat membrane with the characteristics of high sludge concentration of Membrane Bio-Reactor (MBR). The treatment effect of ceramic flat membrane bioreactor on coal chemical wastewater and related influencing factors were studied. The Chemical Oxygen Demand (COD) concentration, ammonia nitrogen concentration, total phenol concentration, and turbidity of coal chemical wastewater could be reduced to below 31.4 mg/L, 3.03 mg/L, 3.76 mg/L, and 0.4 NTU. The ceramic flat membrane bioreactor achieved the optimal removal effect on pollutants when Hydraulic Retention Time (HRT) was 21 h, Dissolved Oxygen (DO) concentration was 3.2–4.0 mg/L and pH was 7.1–7.5. Among them, the total phenol removal ratio reached the maximum value of 95.31 %, and the COD removal ratio remained at 93 % ∼ 94 %, ammonia nitrogen removal ratio was stable at 95 % ∼ 97 %. The microorganisms in the mixture and membrane mainly were aerobic bacteria, and the content of organic-degrading bacteria, nitrifying and denitrifying bacteria was high. The addition of a membrane module not only prevented the loss of activated sludge in the reactor but also kept a high sludge concentration. Meanwhile, the addition of a membrane module also improves the biodiversity and stability of sludge treatment system.

Prospecting for ophiolite-type chromite deposit in Sartohay, West Junggar (NW China): Constraints from geological and geophysical data

Chromite is a critical mineral that is of great significance for the development of metallurgical, chemical, and other industries. In order to study the deep ore prospecting methods of ophiolite-type chromitite, we have carried out plane-profile geological and mineral surveys, as well as high-precision gravity, magnetic, and controlled source audio-frequency magnetotelluric (CSAMT) measurements in the Sartohay, West Junggar. Based on the analysis, interpretation, and inference of multi-source geological information, a three-dimensional (3D) geological model of the typical mining area in Sartohay District was established. The results show that Sartohay ophiolite was occurred in the form of rootless tectonic blocks and generally displayed deformation and metamorphism (e.g., oblique thrust, transverse extrusion, and lateral strike slip). Sartohay ophiolite is in tectonic contact with surrounding strata. Several northwest dipping high-angle thrust faults are developed at the contact sites and inside the ophiolite rock mass, showing a thrust imbricated structure. Meanwhile, ophiolite in the modeling area is a NW-trending monoclinic rock mass. The base surface of the ophiolite is obliquely distributed in an “N-like” shape, and the chromitite bearing lithofacies zones also have a NW-trending distribution. Geophysical data reveal that the studied mining area is characterized by a layered electrical structure in the vertical direction. The upper layer displays a high-resistivity agglomerate and a low-resistivity band distributed alternately, while the lower layer is a complete high-resistivity block. Combined with the deposit characteristics in Sartohay, it is considered that the morphological occurrence, geological structure, lithology, and lithofacies of ophiolite control the spatial distribution of related chromitites. The dunite-harzburgite lithofacies belts, highly strain zones, and strong tectonic alteration belts of the ophiolite rock mass are significant sites for the chromite ore bodies/groups occurrence. This study provides approaches for researching on the production laws of ophiolite-type chromitite and supplys a prospecting pattern for deep concealed orebodies.