Industrial Wastewater Discharge Research Articles

Eco-friendly porous composite of octaphenyl polyhedral oligomeric silsesquioxane and HKUST-1 with hydrophobic-oleophilic properties towards sorption of oils and organic solvents.

The degradation of water bodies caused by organic pollutants from industrial wastewater discharge has made it necessary to develop new functional materials like hydrophobic-oleophilic materials that can efficiently remediate water. It is factual that many of the synthetic methods for creating hydrophobic-oleophilic materials involve the use of toxic or harmful reactants, such as fluorine or sulfur compounds. However, these methods often have significant drawbacks, including being hazardous to the environment, expensive, and complex to utilize. Therefore, there is an urgent need to develop a hydrophobic/oleophilic material that is non-toxic and eco-friendly in order to overcome the existing drawbacks. In this regard, we have proposed a modest and eco-friendly approach for constructing a hydrophobic-oleophilic Ph-POSS@HKUST-1 composite material by solution-assisted self-assembly for the conversion of hydrophilic HKUST-1 into hydrophobic HKUST-1 for separation applications. The incorporation of fluorine-free, low surface energy and hydrophobic POSS into HKUST-1 increased the hydrophobicity and oleophilicity of the system. The synthesized Ph-POSS@HKUST-1 composite material has been thoroughly characterized through FT-IR, PXRD, HR-SEM, BET, and thermogravimetric analysis. It has been observed that the material exhibits a contact angle of 137 ± 4° and shows high selectivity and absorption capacity towards organic solvents and oils from water mixtures. Concurrently, the Ph-POSS@HKUST-1@PDA@sponge has been effectively utilized for the separation of solvents and oils and it has shown more than 95% separation efficiency for up to 15 cycles. It is interesting to note that Ph-POSS@HKUST-1 and the Ph-POSS@HKUST-1@PDA@sponge have outstanding stability in abrasive chemical environments which is due to the presence of a mechanically and chemically stable inorganic-organic hybrid POSS nanocage. In addition, ab initio and DFT calculations elicit that the Ph-POSS@HKUST-1 composite is stabilized through π⋯π stacking instead of the C-H⋯π mode of interaction at the HKUST-1⋯Ph-POSS interface. Further electron density features confirm the interfacial interaction at the interface. Our latest research has led us to propose an eco-friendly and non-toxic hybrid composite material for efficiently tackling the issue of organic solvent and oil pollution in water mixtures.

Recent Advances in Wastewater Treatment by Utilisation of Bio-waste-derived Hydroxyapatite

Hydroxyapatite (HAp) is basically calcium phosphate and the main inorganic component in natural bone and teeth structure. Animal bones and eggshells are mass-generated bio-wastes, and their calcium-rich structure makes them suitable precursors for bioactive HAp synthesis through biomimetic mineralisation. Industrial wastewater discharge is a worldwide alarming problem due to high-capacity industrial-scale processes, and their adverse effects on human health and environment will be encountered long term. Adsorption is the most widely used separation process in wastewater treatment, in which HAp particles can be used as bio-adsorbents for wastewater treatment processes due to their bioactive nature. Utilisation of bio-waste-derived HAp particles for wastewater treatment applications would be a step towards sustainable development and circular economy concepts. It promotes the reuse and recycle rate of bio-wastes as bio-adsorbents through an effective waste management strategy and increases the circularity of the material in the production chain. This study offers a brief overview of articles published in 2023 on the use of bio-waste-derived HAp particles for wastewater treatment.

Petroleum products in wastewater and their properties

Water bodies are polluted by oil and petroleum products from various sources. The primary sources are navigation, accidents on ships and coastal areas, industrial wastewater discharges, surface wastewater from settlements, and transportation crossings of water bodies. Reducing the content of oil products in water bodies is an important task of nature protection, requiring the development of new effective methods of wastewater treatment from oil products. A systematic approach is proposed to solve this problem, including analysis of conditions of wastewater formation, study of phase-disperse composition of pollutants and their physical and chemical properties, and analysis of possible water treatment methods. According to the formation conditions, oily wastewater can be divided into domestic wastewater, surface runoff, and industrial wastewater. Depending on the formation conditions, oil products in wastewater are in different phase-disperse states with different sedimentation and aggregative stability values. Separation methods are most effective for sediment-unstable petroleum product systems and are sufficiently simple and reliable. Sedimentation stable systems of petroleum products in water need to be preliminarily destabilized. This is achieved by adding alkaline acids, mineral coagulants, or organic polyelectrolytes. Wastewater characterized by aggregative stable systems of petroleum products can be treated by degradation methods such as ozonation or sorption.

Amphiphilic Engineering of MoS2-g-C3N4 Nanocomposites into a Mangrove-Inspired Cascade System for Sustainable Drinking Water Production

Drinking water contamination and water shortages are seriously exacerbated by industrial wastewater discharge. However, due to the high complexity of wastewater treatment systems, effective high-concentration pollutant removal and simplified wastewater...

Research on the optimal use of industrial wastewater for sustainable regeneration based on big data background

Industry, as one of the most important areas of water use in China, will use 102.89 billion cubic metres of water in 2020, accounting for 17.7 per cent of the country's total water use, and industrial wastewater discharges will account for about one fifth of the country's sewage discharges. In recent years, positive progress has been made in the recycling of industrial wastewater in China, with the water reuse rate for industries above designated size increasing from 89 per cent in 2015 to 92.5 per cent in 2020, and the water consumption of 10,000 yuan of industrial added value in 2020 decreasing by 39.6 per cent compared with 2015. The current status of research on life cycle carbon emissions of different wastewater recycling technologies and processes was analysed and summarised, taking wastewater recycling products such as reclaimed water, energy, microbial proteins and guano as research targets. The analysis pointed out that wastewater reclamation and value-added utilisation have considerable carbon reduction benefits, but quantitative assessment should be carried out at the system level in conjunction with the utilisation scenarios. This paper researches and analyses industrial wastewater based on the technical foundation of big data. On the basis of analysing the industrial wastewater treatment in China in recent years and at the same time combining the background of big data and treatment technology, it pushes the development of industrial wastewater treatment into a new field and mileage.

Study on the Relationship between Economic Growth and Environmental Pollution in Shanxi Province Based on EKC

Abstract China’s rapid economic development since the reform and opening up has attracted the attention of the world, while a sharp deterioration of the environment accompanies the rapid economic development. Starting from the current situation of economic development and environmental pollution in Shanxi Province, the interaction between economic growth and environmental pollution in Shanxi Province is comprehensively analyzed, and the influence mechanism between the two is revealed. The EKC theoretical econometric model for the relationship between economic growth and environmental pollution in Shanxi Province is constructed and empirically analyzed by combining the multicollinearity test, correlation test, unit root test, and cointegration test to obtain the data required for this study, and at the same time, to determine the research indexes and parameters. The correlation coefficients between GDP per capita and industrial wastewater discharge per capita, industrial exhaust emissions per capita, and industrial solid waste generation per capita in Shanxi province reach more than 0.5, and the Sig values (0.001, 0.004, and 0.005) are less than 0.05, which is a significant correlation, and the R2 coefficient of determination of the fit of the EKC curves of GDP and exhaust emissions is 0.8532, and the expression is y = –0.1169 + 5×102 x – 1×103 x 2 –1.6×103 x 3. This study profoundly reveals the relationship between economic growth and ecological environment and promotes Shanxi Province to achieve the goals of environmental improvement and sustainable economic development.

Sustainable Modelling of Industrial Wastewater Discharges with Big Data Technology

In recent years, with the development of society, the concept of China’s smart city has been sustained development, and sewage treatment, as an important part of urban management, is also developing in the direction of intelligence. With the introduction of the concept of intelligent water, sewage treatment combined with big data, global cloud computing, Internet of Things, mobile Internet and other information technology in-depth use, sewage treatment intelligent control system came into being. The application of big data has made this problem alleviated to a certain extent. The big data referred to here refers to the screening, statistics, analysis, etc. of massive data based on cloud storage and cloud computing platforms, which ultimately results in a set of information with important value. This paper is based on big data technology for industrial wastewater in-depth research and analysis, and adhere to the new era of sustainable development model of industrial wastewater research, for the new integration of people in the field of new exploration and research.

Luminescence and photocatalytic degradation of indigo carmine in the presence of Sm3+doped ZnS nanoparticles

Industrial wastewater discharge is well acknowledged to constitute a significant environmental and public health risk. In addition, synthetic dyes used in the textile sector are major culprits in water pollution. The amount of water polluted by these dyes is simply staggering. We urgently address this issue to protect our planet and health. The degradation of indigo carmine dye in the presence of Sm3+-doped ZnS nanoparticles is reported in this study and characterized by XRD, FTIR, SEM, EDX, TEM, BET, PL, UV, etc. The particle size calculated from the Scherrer equation was 3–12 nm. When excited at 395 nm, Sm3+ undergoes f–f transitions, which are visible as prominent peaks in the photoluminescence spectrum at 559, 595, and 642 nm wavelengths. The catalyst showed vigorous catalytic activity for dye degradation, with a 93% degradation rate when used at 15 mg/L catalyst within 210 min. The reaction was found to have pseudo-first-order kinetics. After applying the Freundlich and Langmuir data, the Langmuir isotherm offered the best fit. The findings indicate that the Sm3+-doped ZnS catalyst might be successfully used in the degradation of dyes present in the environment. Doping with Sm3+ ions can significantly change the photocatalytic breakdown of indigo carmine and the luminescence characteristics of ZnS.

First insights into per-and polyfluoroalkyl substance contamination in edible fish species of the Indus water system of Pakistan

Per- and polyfluoroalkyl substances (PFASs) are a group of emerging contaminants, that have a wide range of applications in industrial and commercial products. The direct discharge of untreated industrial and domestic wastewater into freshwater bodies is a common practice in developing countries, which are the main contributors to PFASs in the aquatic environment. The situation is further worsened due to poor wastewater treatment facilities and weak enforcement of environmental regulations in countries like Pakistan. The current study was designed to assess PFASs contamination in muscle tissues of edible fish species from major tributaries of the Indus System, including Head Panjnad (HP), Head Trimmu (HT), Chashma Barrage (CB), Head Blloki (HB) and Head Qadirabad (HQ). The analysis of target PFAS was performed using ultrahigh-performance liquid chromatography coupled with a quadrupole Orbitrap high-resolution mass spectrometry. The highest levels of ∑17PFASs were observed in S. seenghala, C. mirigala from HB, and C. mirigala from HQ with a mean value of 45.4 ng g-1, 43.7 ng g-1, and 40.8 ng g-1, respectively. Overall, the compositional profile of fish samples was predominated by long-chain PFASs such as PFOA, PFOS, PFHpS, and PFDS. The accumulation of PFASs in fish species is dependent on the physiochemical properties of PFASs, characteristics of the aquatic environment, and fish species. Significant associations of PFASs with isotopic composition (p < 0.05), feeding habits (p < 0.05), and zones (p < 0.05) indicate that dietary proxies could be an important predictor of PFASs distribution among species. The C7–C10 PFASs exhibited bio-accumulative tendency with an accumulation factor ranging from 0.5 to 3.4. However, none of the fish samples had sufficiently high levels of PFOS to cause human health risk (HR < 1). For future studies, it is s recommended to conduct seasonal monitoring and the bioaccumulation pattern along trophic levels of both legacy and emerging PFASs.

Effects of cadmium on gametophyte growth and archegonia development in the endangered floating fern Ceratopteris pteridoides in China

Ceratopteris pteridoides is an endangered annual floating fern in China. This study tested the effect of cadmium on gametophyte growth and archegonia development of the aquatic fern C. pteridoides in culture. The results show that C. pteridoides spores germinated after being treated with different cadmium, but it was not significant compared with the reference group (45.63%). With the increase of cadmium, the rates of hermaphrodite gametophyte, the number of archegonia of C. pteridoides decreased, and archegonium differentiation was delayed gradually, indicating that cadmium caused adverse effects on sexual organ differentiation of C. pteridoides, further exacerbating the endangered status of this species in China. We suggest that it is necessary to pay more attention to protecting the primary habitats of C. pteridoides in China and reduce the impact of human activities from excessive aquaculture and industrial wastewater discharge on the water body in its living water body.

Eco-Friendly Method for Wood Aerogel Preparation with Efficient Catalytic Reduction of 4-Nitrophenol.

The advancement of science and technology and the growth of industry have led to an escalating discharge of domestic sewage and industrial wastewater containing dyes. This surge in volume not only incurs higher costs but also exacerbates environmental burdens. However, the benefits of green and reusable catalytic reduction materials within dye processes are still uncertain. Herein, this study utilized the eco-friendly deep eutectic solvent method (DESM) and the chlorite-alkali method (CAM) to prepare a cellulose-composed wood aerogel derived from natural wood for 4-nitrophenol (4-NP) reduction. The life cycle assessment of wood aerogel preparative process showed that the wood aerogel prepared by the one-step DESM method had fewer environmental impacts. The CAM method was used innovatively to make uniform the chemical functional groups of different wood species and various wood maturities. Subsequently, palladium nanoparticles (Pd NPs) were anchored in the skeleton structure of the wood aerogel with the native chemical groups used as a reducing agent to replace external reducing agents, which reduced secondary pollution and prevented the agglomeration of nanoparticles. Results showed that the catalytic reduction efficiency of 4-NP can reach 99.8%, which shows promises for applications in wastewater treatment containing dyes. Moreover, investigation of the advantages of preparation methods of wood aerogel has important implications for helping researchers and producers choose suitable preparation strategies according to demand.

The impact of full-scale armed conflict on water bodies as water supply sources

Water resources are the basic component of sustainable development of the country. Water resources are unevenly distributed across the territory of Ukraine, most settlements and enterprises located in the northern, eastern and southern regions use surface water for water supply. The armed conflict on the territory of Ukraine directly and indirectly affects the state of water bodies, as well as the provision of basic human needs - clean drinking water. With the beginning of conflict on the territory of Ukraine in 2014, water resources regularly suffer from russian terrorist actions. The aggressor uses water resources as natural obstacles, uses the destructive effect of water to kill Ukrainians and cause maximum damage to Ukrainian economy. Also, the destruction of the water treatment and water supply system is used by russian troops as a means of pressure creating water scarcity and terrible sanitary conditions in populated areas. The impact on water resources during armed conflicts in different parts of the world have common features and significant features depending on the level of the conflict and the technology of the water supply system itself. First of all, the impact of armed conflicts on water resources is direct and indirect. The direct impact on water resources as water sources is the direct destruction of water reservoirs, water intake structures and water pipes, contamination of water bodies with the remains of sunken military equipment, mines and chemicals released into the water during the decomposition of weapons. Indirect impact on water sources is in some cases more threatening than direct. The destruction of containers with oil products, chemical substances, fertilizers, which with rainwater or directly fall into water bodies, has much greater damage than the direct impact of sunk military equipment. Forest and meadows fires and other surface cover damages lead to the reduction of the lag time to the river on the catchment area, floods increasing, flooding of larger areas, increasing amount of litter, chemical pollution, and plastics in the rivers. In most of the military conflicts described in the literature, a significant deterioration of water quality in rivers is noted, associated with the discharge of both domestic and industrial wastewater. There is the destruction of wastewater treatment plants, the inability to deliver chemicals for treatment, the inability to control unauthorized discharges of wastewater leads to the contamination of the surface water sources. The report analyses the results of surface water quality researches which officially published by the Water Resources Agency of Ukraine and other governmental and scientific organizations. Monitoring of the surface water quality is carried out on the controlled part of the Ukraine, it is not yet possible to assess the consequences of armed conflict and russian activities on the captured territories.

Assessment of heavy metal accumulation and health risk in three essential edible weeds grown on wastewater irrigated soil

The main problem facing Egypt recently is the shortage of available water resources. Therefore, farmers resort to use wastewater for irrigation. So, the present work aims to assess the impacts of wastewater irrigation on the productivity of three edible weeds (Cichorium endivia, Sonchus oleraceous and Beta vulgaris) and its effect on the nutritional value of plants and its risk on human health. This study will focus on Shibin Al Kanater region, and the physicochemical characteristics of drainage water, canal water, drainage water-irrigated soils and canal-irrigated soils were estimated. The vegetative and traits of edible weeds were determined including their photosynthetic pigments, organic and inorganic nutrients content, and heavy metals content. The health risk index (HRI) associated with consumption of polluted plants was created using the estimated exposure factor of a crop to the oral reference dosage of the toxic metal. The main results showed that biomass productivity of S. oleraceous, B. vulgaris and C. endivia increased due to drainage water irrigation with increasing percentage as 27.9, 19.6, and 19.1%, respectively. Irrigation with drainage water significantly increased the photosynthetic pigments of edible weeds. Irrigation with drainage water increased carbohydrate content, crude protein, total soluble sugar, and gross energy in all studied weeds. C. endivia, S. oleraceus and B. vulgaris plants irrigated with canal and drainage water could accumulate Fe, Zn, Cu, and Co in their roots. C. endivia, S. oleraceus and B. vulgaris plants irrigated with canal water indicated HRI more than the unit for Mn, Cu, Pb, and Cd. This research advises that regulation be put in place to prohibit irrigation using untreated drainage and to restrict the discharge of industrial, domestic, and agricultural wastewater into irrigation canals.

Comprehensive assessment of occurrence, temporal-spatial variations, and ecological risks of heavy metals in Jiaozhou Bay, China: A comprehensive study

Heavy metals play a significant role in marine ecosystems, exerting notable impacts on the environment and human health. In this study, water, sediment, and aquatic organism samples from Jiaozhou Bay were investigated to comprehensively assess the distribution, temporal-spatial variations, and ecological risks of heavy metals. The results indicate that pollution from industrial wastewater discharge contributes to regional differences in the distribution of heavy metals, possibly being a major source of Zn, Cr, Cd, and Hg (r > 0.7, p < 0.05). Biological and physicochemical processes influence the distribution of Zn, Cr, and Pb in the water and sediment. Hg exhibits a polluted state in both the water and sediment, with As and Hg being the two highest-risk heavy metals in water and sediment, respectively. Among the organisms, crustaceans show significantly higher levels of heavy metal content and accumulation compared to mollusks and fish (p < 0.05), and the bioamplification of heavy metals occurs in the sediment-Rapana venosa-Portunus trituberculatus biological pathway. Portunus trituberculatus, Charybdis japonica, Oratosquilla oratoria, and Octopus ocellatus could pose risks to human health, especially for children and vulnerable populations. This study aims to enhance our understanding of the current status of heavy metal pollution in Jiaozhou Bay and to provide a scientific basis and favorable support for the ecological environmental protection and prevention of ecological risks associated with heavy metal pollution in Jiaozhou Bay and other bays in China.

Horizontal ecological compensation policy and water pollution governance: Evidence from cross-border cooperation in China

Cross-border cooperation can overcome the administrative boundaries of water pollution governance, and the two-way ecological compensation model emerges as a solution to transforming government-financed payments into locally-driven development initiatives. This study presents a tripartite evolutionary game model for two-way ecological compensation, incorporating city-level data, and employs time-varying difference-in-differences to estimate the incentive impact of China's cross-border horizontal ecological compensation policy on water pollution governance during 2006–2018. Furthermore, this study aligns state-controlled monitoring stations with their respective administrative districts and enhances water pollution indicators obtained from these stations for a more comprehensive policy assessment. The results show that horizontal ecological compensation effectively reduces the prevalence of industrial wastewater discharges and associated water pollution; this effect is more pronounced upstream (20.94%) compared to downstream (16.01%). However, it does not significantly impact urban sewage treatment, agricultural non-point source pollution, or lake water quality and eutropHication. In addition to promoting horizontal coordination between upstream and downstream regions, vertical central governmental inspections are crucial for effectively stimulating and guaranteeing horizontal collaborative governance between upstream and downstream local governments. These results provide strong empirical evidence in favor of expanding horizontal ecological compensation initiatives throughout the entire river basins, as well as in other countries or regions.

Мікробіологічна оцінка стічних вод промислових підприємств м. Києва та Київської області

The aim: industrial wastewater microbiological monitoring and its effect on the drainage water condition. Purpose: microbiological monitoring of industrial wastewater and its impact on the state of surface waters. Materials and methods: wastewater quality evaluation was performed according to the parameters: the lactose-positive coliforms (LPC) count, the coli index, coliphages count and the pathogenic enterobacteria presence. Results: wastewater (WW) treated with full biological treatment and disinfection, UV radiation, chlorination and the cleansing structures use was studied. Industrial WW samples met the 1-2 quality class requirements. 7 food processing wastewater samples did not meet the discharge into an open water requirements in terms of LCP count, which was in the range from 2300 CFU/dm3 to 46000 CFU/dm3, it indicates water fecal pollution. At the same time, according to the coliphages count, these samples belonged to the 2nd quality class. Surface water samples comparative analysis before and after the industrial wastewater discharge shows that the investigated wastewater discharge did not lead to surface watercourse microbiological contamination. Conclusions: according to the 41 industrial wastewater reuse samples microbiological quality monitoring results for the period January 2021-June 2023, 34 WW samples were met the 1-2 quality class requirements, which indicates their satisfactory purification and the discharge possibility into an open water body. 7 samples did not meet the LCP number requirement, which indicates poor-quality purification and their fecal contamination. It was established that the surface watercourse before and after the reuse wastewater discharge, according to the LCP count, the coli index, coliphages count belong to the 1-2 quality class. The investigated industrial wastewater discharge did not exceed the allowance allocation and did not lead to surface waters microbiological contamination.

Experimental investigation on the hybrid system of mechanical vapor recompression and hollow fiber vacuum membrane distillation applied for wastewater treatment

In order to achieve zero discharge and resource utilization of industrial high salt wastewater, a hybrid system of mechanical vapor recompression (MVR) and hollow fiber vacuum membrane distillation (HFVMD) was constructed, and several experiments of air tightness, single working condition and multiple working conditions were carried out with ammonium chloride solution as feed, then thermal economic performance were evaluated via a single factor analysis method. The obtained results showed that the system had excellent airtightness to ensure normal evaporation experiment, and high separation efficiency of 99.9% and lower evaporation energy consumption to achieve high efficient separation by combining the advantages of the hydrophobic membrane evaporation and latent heat recovery in view of MVR and HFVMD technologies. Furthermore, increasing feed temperature and feed flow rate increased evaporation rate and decreased evaporation energy consumption, while increasing feed concentration decreased evaporation rate and increased evaporation energy consumption. Finally, the single factor analysis indicated that total investment cost, annual operation cost and annual evaporation capacity were the main factors while environmental cost and equipment service life were the secondary factors which affected the specific evaporation cost. The above research provides theoretical and experimental bases for the development of the proposed system in the future.

Facile Coaxial Electrospinning Synthesis of Polyacrylonitrile/Cellulose Acetate Nanofiber Membrane for Oil-Water Separations.

Oil-contaminated water and industrial oily wastewater discharges have adversely affected aquatic ecosystems and human safety. Membrane separation technology offers a promising solution for effective oil-water separation. Thus, a membrane with high surface area, hydrophilic-oleophobic properties, and stability is a promising candidate. Electrospinning, a straightforward and efficient process, produces highly porous polymer-based membranes with a vast surface area and stability. The main objective of this study is to produce hydrophilic-oleophobic polyacrylonitrile (PAN) and cellulose acetate (CA) nanofibers using core-shell electrospinning. Incorporating CA into the shell of the nanofibers enhances the wettability. The core PAN polymer improves the electrospinning process and contributes to the hydrophilicity-oleophobicity of the produced nanofibers. The PAN/CA nanofibers were characterized by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, X-ray diffraction, and surface-wetting behavior. The resulting PAN/cellulose nanofibers exhibited significantly improved surface-wetting properties, demonstrating super-hydrophilicity and underwater superoleophobicity, making them a promising choice for oil-water separation. Various oils, including gasoline, diesel, toluene, xylene, and benzene, were employed in the preparation of oil-water mixture solutions. The utilization of PAN/CA nanofibers as a substrate proved to be highly efficient, confirming exceptional separation efficiency, remarkable stability, and prolonged durability. The current work introduces an innovative single-step fabrication method of composite nanofibers, specially designed for efficient oil-water separation. This technology exhibits significant promise for deployment in challenging situations, offering excellent reusability and a remarkable separation efficiency of nearly 99.9%.

Impact of industrial robots on environmental pollution: evidence from China

The application of industrial robots is considered a significant factor affecting environmental pollution. Selecting industrial wastewater discharge, industrial SO2 emissions and industrial soot emissions as the evaluation indicators of environmental pollution, this paper uses the panel data model and mediation effect model to empirically examine the impact of industrial robots on environmental pollution and its mechanisms. The conclusions are as follows: (1) Industrial robots can significantly reduce environmental pollution. (2) Industrial robots can reduce environmental pollution by improving the level of green technology innovation and optimizing the structure of employment skills. (3) With the increase in emissions of industrial wastewater, industrial SO2, and industrial dust, the impacts generated by industrial robots are exhibiting trends of a “W” shape, gradual intensification, and progressive weakening. (4) Regarding regional heterogeneity, industrial robots in the eastern region have the greatest negative impact on environmental pollution, followed by the central region, and the western region has the least negative impact on environmental pollution. Regarding time heterogeneity, the emission reduction effect of industrial robots after 2013 is greater than that before 2013. Based on the above conclusions, this paper suggests that the Chinese government and enterprises should increase investment in the robot industry. Using industrial robots to drive innovation in green technology and optimize employment skill structures, reducing environmental pollution.

Insights into dynamic evolution of combined scaling-biofouling in reverse osmosis

Although extensive research has focused on individual membrane fouling, there is still a lack of studies regarding combined scaling-biofouling, which is more commonly encountered in practical membrane desalination processes due to the coexistence of inorganic scalants and microorganisms. To our best knowledge, it is the first study that elaborated the dynamic evolution of combined scaling-biofouling in the reverse osmosis (RO) cross-flow filtration process, compared with gypsum scaling and biofouling alone. The results indicated that scaling ions (35 mM CaCl2 + 20 mM Na2SO4) stimulated protein secretion but inhibited that of polysaccharide and total organic carbon (TOC). The gradually formed scaling layer evidently enhanced the hydrophilicity of the fouled membrane, and consequently improved the repulsion of membranes against microbes and the secreted extracellular polymeric substances (EPS), proved by the augmented energy barrier for microbial adhesion through XDLVO interfacial energy analysis, and resulted in the slower flux decline at the later stage of combined scaling-biofouling. In the other perspective, microorganisms and EPS diminished the (020), (021) and (041) facets of gypsum crystals, decreased the crystallinity and size of gypsum crystals, and thus prolonged the formation of inorganic scaling. It was suggested that scaling ions should be effectively controlled through pretreatment as they contributed to more rapid flux decline, as the cleaning efficiency of Ca2+ ions decreased from 84.8 % to 57 % after they combined with EPS, and thus chiefly contributed to reversible membrane fouling resistance. This study fills in the knowledge gap on interactions between gypsum scaling and biofouling during the formation of combined scaling-biofouling in RO filtration, which had significant environmental effects under the strict industrial wastewater discharge standards and zero liquid discharge (ZLD) requirements.