By a simple and convenient method of using epichlorohydrin as linkages, a novel Alternanthera philoxeroides (AP) derivative modified with diethylenetriamine (DAP) was synthesized, which can remove copper(II) ions (Cu(II)) in the water environment efficiently. The adsorption capacity of DAP for Cu(II) under various factors was measured using ultraviolet spectrophotometer. The adsorption capacity and removal ratio were 19.33 mg/g and 95.57% at pH 5.5 and 298 K. The kinetic and equilibrium study shows that pseudo-second-order kinetic (R² = 0.9964) and Langmuir isotherm models (R² > 0.982) could properly describe DAP adsorption behaviors, and thermodynamic parameters indicate a spontaneous endothermic process (ΔG = − 3.6636 kJ/mol). The combined results of SEM, XRD, FTIR, and XPS analyses reveal that the dominant contribution for enhancement in Cu(II) adsorption is made by the formation of an amino group. And the adsorption mechanism is mainly the complexation reaction. The adsorption efficiency of DAP remained above 72.06% after 6 cycles of adsorption-desorption, which indicated that DAP has good regenerability and stability. All the results suggest that DAP could serve as promising adsorbents for Cu(II) pollution minimization.

A gradual increase in the importance of water environment infrastructure has provided an opportunity to bring in various initiatives for the supply of sewage. Such initiatives include the dissemination of public sewage systems and the use of subcontractors in management of sewage systems. However, despite the existence of various methods to increase the rate of sewage supply, there are few studies analyzing each alternative in terms of social, economic, and environmental aspects. Therefore, we investigated investment directions for water environment infrastructure facilities related to the supply of sewage treatment systems in rural areas through cost-benefit analysis. We analyzed the economic costs and social benefits of two sewage treatment systems: installation of a public sewage treatment system and utilization of a private sewage treatment system via service contract. When we considered only economic costs and benefits, the benefit-cost ratio for the public system (0.02) was smaller than that for the private system (0.264). However, the results of the two alternatives changed when we considered the social benefits to people in urban areas from establishment of public sewage treatment systems in rural areas. To be specific, by considering the social benefits for non-rural areas, this study found that the benefit-cost ratio for the public system increased to 0.267, which was higher than the ratio for the private system. Based on these results, we propose appropriate operations and management plans for supplying sewage treatment systems to rural areas. Further, this study indicates that policymakers who conduct cost-benefit analyses of infrastructure related to water environments should consider all social, environmental, and economic factors that can alter the analysis results.

Bisphenol A (BPA), diethyl phthalate (DEP), and carbamazepine (CBZ) have been widely used in chemical and pharmaceutical fields, and their residues are detected in various environments. Therefore, to find a suitable method for removing the compounds from an aqueous solution, an adsorption method by granular activated charcoal (AC) was studied. To investigate the adsorption properties of AC, its kinetics, equilibrium, pH effects, and regeneration of AC were examined. Moreover, its surface properties (i.e., surface area, pore volume, functional groups, and surface charge) were characterized by N₂ adsorption and desorption isotherm, Fourier transform infrared (FTIR), and zeta potential analyses. Experimental results show that AC has high removal efficiencies for the target compounds at the low initial concentration as well as high estimated adsorption capacities (qₘ) for DEP, BPA, and CBZ, whose values were 293.4 ± 18.8, 254.9 ± 16.2, and 153.3 ± 1.61 mg/g, respectively. In comparison with other adsorbents based on previously reported results, AC was shown to have generally higher removability for the three compounds than others. Moreover, it was observed that AC’s ability to adsorb DEP and BPA was dependent on pH because of hydrolysis and ionization, respectively. Meanwhile, there is no pH effect for CBZ adsorption by AC. After 3 cycles of adsorption/desorption, AC still maintained 92, 100, and 82% of initial adsorption capacities for DEP, BPA, and CBZ, respectively. Therefore, the AC is an effective adsorbent for the removal of endocrine-disrupting chemicals and pharmaceuticals from aqueous solution.

A valuable method for the efficient removal of sulphonamides from wastewater using protein powder extracted from the seeds of Moringa stenopetala is presented in this study. The surface morphology, crystallinity and functional groups of protein powder were characterised by SEM, XRD, FTIR and Raman spectrometry. Parameters that affect the removal of sulphonamides, such as concentration, the adsorbent dosage and pH, were optimised. The method was applied to a real wastewater sample collected from the Daspoort Wastewater Treatment Plant located in Pretoria, South Africa. The percentage removal under optimum conditions was observed to be 86.4 to 95.1% for the aqueous solution of a mixture of standards and from 83.0 to 90.5% and 75.2 to 87.7 % for the effluent and influent wastewater samples respectively. Therefore, proteins extracted from Moringa stenopetala seeds demonstrated to be effective and environmentally friendly material for possible application in water treatment in general and wastewater treatment in particular.

China, the largest developing country, is the world largest cement producer and the largest cement-consuming nation. Although China’s cement output reached its peak in 2014, regions, i.e., Fujian and Yunnan provinces, were no peaking until 2016. At the same time, rare studies referred to China’s cement consumption and CO₂ emissions from the perspective of cement consumption at the provincial level. We developed the S-Logistic, polynomial model, and ARIMA model to study the peaking time of cement consumption at the provincial level, and we also projected China’s cement consumption and CO₂ emissions toward 2030. Meanwhile, the discrepancies of peaking time and cumulative cement consumption per capita (CCCPC) among provinces were also studied based on GDP per capita and urbanization rate (UR). The results are that the CCCPC respectively in the range of 22–34 ton, 18–25 ton, and 17–27 ton in the eastern, intermediate, and western zone when cement consumption reached its peak. We draw the following conclusions that the CCCPC in 2030 could reach ~ 43 ton and the projected cement consumption is ~ 1252.72 Mt, which accounts for 50% of that in 2017, and cement CO₂ emissions are at the range of 488.19–510.90 MtCO₂ in 2030. Furthermore, capacity replacement, controlling new capacity and eliminating backward capacity are significant of greenhouse gas emission reduction not only for China, but also for the global cement industry.

As human demand for ecosystem services (ES) continues to increase, ES assessments have gradually become a popular research topic. Among ES, cultural ES (CES) are often overlooked and are difficult to measure during research because of their invisibility. However, the importance and usage of CES increase with supply and demand, which is key to linking the ecosystem with human well-being. This paper quantitatively evaluates various cultural services and generates corresponding Value Index (VI) maps; it then further explores the current dynamics of supply and demand. We selected Cuihua Mountain (CM) as the study area, and we applied the Social Values of Ecosystem Services (SolVES) model to evaluate CES and generated five specific VI maps to indicate the potential service stock (ES capacity). The actual supply (ES supply) is based on the attribute of the visibility of observation points on leisure routes, and the visitors (ES demand) to the service come from socio-economic data as a measure of the rates of access to entertainment venues. The supply and demand relationship (ES budget) solves the significant problems related to the oversupply and shortage of ES in space. The results showed that the CES supply power of CM is greater than the actual demand; thus, there is great potential for future development. This study also provided a reference and guidance for environmental decision-making and development in other regions.

This study investigates the spatiotemporal variability of major and trace elements, dissolved organic carbon (DOC), total dissolved solids (TDS), and suspended particulate matter (SPM) in surface waters of several hydrosystems of the Loire River watershed in France. In particular, this study aims to delineate the impact of the abovementioned water physicochemical parameters on natural iron and manganese physical speciation (homoaggregation/heteroaggregation) among fine colloidal and dissolved (< 10 nm), colloidal (10–450 nm) and particulate (> 450 nm) phases in Loire River watershed. Results show that the chemistry of the Loire River watershed is controlled by two end members: magmatic and metamorphic petrographic context on the upper part of the watershed; and sedimentary rocks for the middle and low part of the Loire. The percentage of particulate Fe and Mn increased downstream concurrent with the increase in SPM and major cations concentration, whereas the percentage of colloidal Fe and Mn decreased downstream. Transmission electron microscopy analyses of the colloidal and particulate fractions (from the non-filtered water sample) revealed that heteroaggregation of Fe and Mn rich natural nanoparticles and natural organic matter to the particulate phase is the dominant mechanism. The heteroaggregation controls the partitioning of Fe and Mn in the different fractions, potentially due to the increase in the ionic strength, and divalent cations concentration downstream, and SPM concentration. These findings imply that SPM concentration plays an important role in controlling the fate and behavior of Fe and Mn in various sized fractions. Graphical abstract Physical speciation by heteroaggregation of (Fe-Mn) compounds: high [SPM] → [Fe-Mn] particulate faction; low {SPM] → [Fe-Mn] colloid-dissolved fraction.

In this study, a new type of composite material, namely modified biochar (MBC), was synthesized by loading the magnetic ferromanganese oxide nanoparticles on pine biochar. BET, SEM, and FTIR were employed to analyze the surface properties and pore structures of MBC. In addition, XRD was adopted to examine the crystal structure of MBC. Characterization results showed that the surface area and porosity of MBC have been greatly improved, and the functional groups have been introduced by ferromanganese oxides. Adsorption experiments of tetracycline hydrochloride (TC) including kinetics, isotherms, thermodynamics as well as the influence of pH, salt ion strength, and the environmental risk of MBC, were evaluated. The results revealed that the experimental data conformed to the pseudo-second-order kinetic model and the Freundlich isotherm model. In the adsorption process, MBC showed excellent adsorption ability (maximum capacity for TC 100.74 mg g⁻¹) to BC (33.76 mg g⁻¹). In isotherm experiments, the maximum adsorption capacity of TC by MBC reached 177.71 mg g⁻¹. Toxicity studies showed that the MBC had no harm to the environment. To conclude, MBC has great potential for applications in removing TC from water.

We investigated the association between diabetes and p,p′-DDT (dichlorodiphenyltrichloroethane) in blood of Mexican Americans who participated in the 1999–2004 National Health and Nutrition Examination Survey (NHANES). In this sample, p,p′-DDT were missing in 50% of subjects and we used multiple imputation (MI) to address the problem. Compared to ignoring the missing data, MI led to a more robust threshold for the p,p′-DDT reference category. Whereas previously p,p′-DDT ≤ 0.0860 ng/g was used as the reference category, using MI, we were able to use p,p′-DDT < 0.0574 ng/g as the reference category to study the association between p,p′-DDT and diabetes via logistic regression. In this analysis, p,p′-DDT ≥ 0.0750 ng/g was associated with an odds ratio of 1.99 (95% CI 1.09–3.61) for diabetes and 4.20 (95% CI 1.93–9.12) for diabetic nephropathy. The reference category for diabetes without nephropathy outcome stayed consistent after MI but our analysis confirmed that p,p′-DDT > 0.0860 ng/g was associated with diabetes without nephropathy with an odds ratio of 1.89 (95% CI 1.09–3.27). Our study showed that MI can be effectively used to deal with missing at random data in persistent organic pollutants measured in the 1999–2004 NHANES.

Sulfur dioxide emissions have been regulated at a global scale; sulfur (S) deposition no longer contributes to soil acidification instead of an alleviation effect in temperate regions; however, it remains unclear whether S deposition still contributes to soil acidification in the tropics. The Pearl River Delta (PRD), South China, has been suffering serious soil acidification, but the contribution of S deposition was ignored because of the regulation of S emission since 2001. Here, we chose the evergreen broadleaf forests, which are the typical forest type at the regional scale in PRD to examine the contribution of S deposition and its characteristics in this acidification, based on an established urban–rural gradient in the range of 260 km. A substantial acidification was evidenced by the significant decline of soil pH from rural to urban sites, with mean pH values decreased by more than 0.60 U through the whole 40-cm depths. However, there was no significant difference in soil pH from 0–10 cm, 10–20 cm, and to 20–40 cm at each site (P > 0.05). Acid-neutralizing capacity (ANC) showed a similar trend to soil pH, with a significant decline along the urbanization gradient and no significant effect of soil depths. Soil sulfate (SO₄²⁻), as the most abundant species in ANC, contributed greatly to soil acidification for the whole 40-cm depth, as shown by the significant positive relationships between it with soil pH and base cations. Soils also exhibited the depletion of base cations with low base saturation (< 20%) and the release of Al and Fe. Our research demonstrated that the severe soil acidification in the PRD region has extended to the subsoil level (40-cm depth), and S deposition is still an important driver to this acidification. Therefore, both recovering the acidified soils and controlling the acidifying pollutants, especially S, are particularly difficult in southern China.