As the largest carbon dioxide (CO₂) emitter, China exists obvious regional inequality in per capita CO₂ emissions. However, such inequality and its dynamic change for recent years have not been systematically studied. In this paper, we evaluate China’s regional inequality in per capita CO₂ emissions during 1997–2016 using the Theil index and decompose it into within-region and between-region components based on eight regions. Furthermore, we apply the decomposition analysis to explore the contribution of different factors to such inequality, including the carbonization index, energy intensity, energy structure, labor productivity, and employment rate. The results show that China’s overall inequality in per capita CO₂ emissions reduced first and increased thereafter during 1997–2016. Within-region inequality was the main source of overall inequality in 1997–2004, while between-region inequality contributed more during 2005–2016. Labor productivity and energy intensity were the two main drivers of overall inequality, but their contributions to the inequality between regions and within regions were quite different. Moreover, the impact of energy structure and carbonization index on regional inequality in per capita CO₂ emissions significantly increased during 2012–2016, which was related to the efforts made by local governments to improve the energy mix. Policy implications were given according to the above conclusions to improve regional inequality in per capita CO₂ emissions.

Wastewater-based epidemiology is an innovative approach to estimate a population’s intentional and unintentional consumption of chemicals based on biomarker assays found in wastewater. This method can provide real-time objective information on the xenobiotics to which a population is directly or indirectly exposed. This approach has already been used to assess the population exposure to four classes of pesticides: organochlorines (chlordecone), triazines, organophosphates, and pyrethroids. This review aims to obtain the data (excretion rates) and characteristics (pesticide and metabolites stability, including in-sewer one) for other pesticides to broaden the scope of this new method. Excretion rates and stability descriptions for 14 pesticides, namely 2,4-D, aldrin, carbaryl, chlorobenzilate, dieldrin, diquat, ethion, glufosinate, glyphosate, folpet, malathion, parathion, penconazole, and tebuconazole, will be discussed in a practical framework.

MIL-100(Fe), an environmental-friendly and water-stable metal–organic framework (MOF), has caught increasing research and application attention in the recent decade. Thanks to its mesoporous structure and eximious surface area, MIL-100(Fe) has been utilized as precursors for synthesizing various porous materials under high thermolysis temperature, which makes the derivatives of MIL-100(Fe) pretty promising candidates for the decontamination of wastewater. Herein, this review systematically summarizes the versatile synthetic methods and conditions for optimizing the properties of MIL-100(Fe) and its derivatives. Then, diverse environmental applications (i.e., adsorption, photocatalysis, and Fenton-like reaction) of MIL-100(Fe) and its derivatives and the corresponding removal mechanisms are detailed in the discussion. Finally, existing knowledge gaps related to fabrications and applications are discussed to close and promote the future development of MIL-100(Fe) and its derivatives toward environmental applications. Graphical abstract

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High alkali-metal sulfate contents in ash from high-alkali coal are a result of the alkali metals’ strong sulfur-capturing capacity. In this work, the effects of sulfates in ash on SO₃ formation were investigated by adding alkali-metal sulfates (Na₂SO₄ and K₂SO₄) to ash and performing experiments to simulate SO₃ formation. The results show that Na₂SO₄ and K₂SO₄ addition significantly increased SO₃ formation and the formation rate increased with increasing temperature. The formed SO₃ concentration increased by 6.8 ppm (adding Na₂SO₄) and 6.3 ppm (adding K₂SO₄) at 1000 °C. These increases are the result of SO₃ release from sulfate during the formation of aluminosilicates such as NaAlSi₃O₈ (albite), NaAlSiO₄ (nepheline), KAlSiO₄ (kalsilite), and KAlSi₃O₈ (feldspar) with the SiO₂ and Al₂O₃ in the ash. This was confirmed by X-ray diffraction (XRD) and thermodynamic calculation. In addition, increasing the SO₂ concentration increased the SO₃ concentration and decreased the SO₃ conversion ratio. Graphical abstract Note: This data is mandatory.

Membrane distillation (MD) has a high heat requirement. Integrating MD with thermophilic bioreactors could remedy this problem. A laboratory-scale thermophilic anaerobic granular sludge membrane distillation bioreactor (ThAGS-MDBR) was used to treat wastewater with a high organic loading rate (OLR). Waste heat from ThAGS was used directly for the MD process to reduce energy consumption. The result demonstrated that the ThAGS-MDBR system achieved a high-efficiency removal of chemical oxygen demand (more 99.5%) and NH₄⁺-N (96.4%). Furthermore, the highest methane production from the proposed system was 332 mL/g CODᵣₑₘₒᵥₑd at OLR of 16 kg COD/m³/day. Specifically, an aggregate of densely packed diverse microbial communities in anaerobic granular sludge was the main mechanism for the enhancement of bioreactor tolerance with environmental changes. High-quality distillate water from ThAGS-MDBR was reclaimed in one step with total organic carbon less than 1.7 mg/L and electrical conductivity less than 120 μS/cm. Furthermore, the result of the DNA extraction kit recorded that Methanosaeta thermophila was a critical archaea for high COD removal and bioreactor stability.

This study was aimed to evaluate the physiological reproductive end points (sex ratio, gametogenic cycle) and biological indices (condition index, length–weight relationship) in D. trunculus collected monthly over the year 2016, from two sites of the Gulf of Annaba (Northeast Algeria): El Battah (relatively unpolluted site) and Sidi Salem (polluted site). The results showed that gametogenesis takes place from December to August in both sites, with an autumnal resting phase. Also, the spawning occurred between March and August with two major spawning phases: April and August in El Battah vs May and August in Sidi Salem. The condition index showed a significant decrease in Sidi Salem site and positive correlation with gonad index. Moreover, the sites exert a significant effect on the allometric relationship and no significant effect on sex ratio. The observed reproductive events are discussed with the changes in the biological indices and the levels of pollution in the studied sites.

Nowadays, humanity is consuming unsustainably the planet’s resources. In the scope of energy resource consumption, e.g., the intense use of fossil fuels has contributed to the acceleration of climate changes on the planet, and the overriding need to increase energy efficiency in all sectors is now widely recognized, aiming to reduce greenhouse gases (GHG) emissions by 69% in 2030. Largely due to climate changes, water has also become a critical resource on the planet and hydric stress risk will rise significantly in the coming decades. Accordingly, several countries will have to apply measures to increase water efficiency in all sectors, including at the building level. These measures, in addition to reducing water consumption, will contribute to the increase of energy efficiency and to the decrease of GHG emissions, especially of CO₂. Therefore, the nexus water energy in buildings is relevant because the application of water efficiency measures can result in a significant contribution to improve buildings’ energy efficiency and the urban water cycle (namely in abstraction, treatment, and pumping). For Mediterranean climate, there are few studies to assess the extent and impact of this nexus. This study presents the assessment of water-energy nexus performed in a university building located in a mainland Portugal central region. The main goals are to present the results of the water and energy efficiency measures implemented and to assess the consequent reduction of water, above 37%, and energy (30%) consumption, obtained because of the application of water-efficient devices and highly efficient light systems in the building. The water efficiency increase at the building level represents at the urban level an energy saving in the water supply system of 406 kWh/year, nearly 0.5% of the building energy consumption, with a consequent increase in the energy efficiency and in the reduction of GHG emissions. Complementarily, other energy-efficient measures were implemented to reduce the energy consumption. As the building under study has a small demand of domestic hot water with no hydro pressure pumps and has a small water-energy nexus, it was concluded that the significant reduction of the building energy consumption did not influence the indoor comfort.

Coal fly ash (FA) is a solid waste produced in coal combustion. This study focused on the removal of Cd²⁺ from wastewater by a newly synthesized adsorbent material, the low-temperature and sodium hydroxide–modified fly ash (SHM-FA). The SEM and BET analyses of SHM-FA demonstrated that the adsorbent was porous and had a huge specific surface area. The XRF, XRD, FTIR and TGA characterization showed that SHM-FA has an amorphous structure and the Si–O and Al–O in the fly ash dissolved into the solution, which improved the adsorption capacity of Cd. The results indicated that SHM-FA has desired adsorption performance. The adsorption performance was significantly affected by the dosage, starting pH, Cd²⁺ initial concentrations, and temperature, as well as adsorption time. In the optimal conditions, the removal efficiency and adsorption capacity of Cd²⁺ by SHM-FA were 95.76% and 31.79 mg g⁻¹, respectively. The experiment provided clearly explained adsorption kinetics and isotherms. And the results confirmed that the adsorption behavior was well described by the pseudo-second-order kinetic and Langmuir isotherm model, which means that the adsorption of Cd²⁺ was controlled by SHM-FA through surface reaction and external diffusion process. In addition, the recycling of SHM-FA for reuse after Cd²⁺ adsorption showed high removal efficiency up to six times of use. Therefore, it can be concluded that SHM-FA is a low-cost adsorbent for Cd²⁺ removal from wastewater.

Recovery, physicochemical and functional characteristics of proteins recovered from different meat processing wastewater streams were revealed in the present study. Wastewaters from surimi processing (SPW) and slaughterhouses, namely fish (FSW), cattle (CSW), poultry (PSW), and goat (GSW), exhibited protein, fat, ash, moisture, and microbial load in the range of 1.28–7.04%, 0.86–2.34%, 0.02–0.80%, 89.81–97.44%, and 5.33–5.81 CFU/mL, respectively. Among the wastewaters, SPW presented slightly higher protein (7.04%), fat (2.34%), and ash (0.80%) contents (P < 0.05). Furthermore, proteins recovered from SPW (SPWP) and FSW (FSWP), CSW (CSWP), PSW (PSWP), and GSW (GSWP) presented yield, protein, fat, ash, and moisture content in the range of 55.54–76.81%, 65.86–78.22%, 7.26–11.45%, 4.58–11.75%, and 5.67–14.79%. All protein samples displayed higher essential amino acid (EAA) content with leucine (8.47–14.52 g/100 g) as a predominant amino acid. GSWP and SPWP scored the highest and lowest EAA contents, respectively. SPWP displayed myofibrillar proteins as dominant proteins, while slaughterhouses’ wastewater proteins showed blood proteins as major proteins. β-Sheet is the major secondary structure presented by all protein samples. SPWP showed the highest lightness value as compared to other protein counterparts (P < 0.05). All protein samples from slaughterhouse wastewaters had the lowest protein solubility at pH 4.5. However, SPWP presented minimum solubility at pH 5.5. Among all protein samples, SPWP presented slightly higher water holding capacity and foaming property (P < 0.05), whereas FSWP displayed slightly higher emulsion property (P < 0.05). Overall, all meat processing wastewater streams served as good sources of high-quality proteins, which could be used as protein ingredients in animal feed formulation.