Among the Cu(II) removal methods, adsorption is a favorable technique and has attracted large attention because of its effectiveness and low cost. In quest of seeking for a favorable adsorbent with a high Cu(II) adsorption capacity and excellent reusability, researchers have paid much attention to hydrogels with three-dimensional networks. In this study, a novel hydrogel (P(AMPS-co-VDT) hydrogel) based on free-radical polymerization was synthesized with ionic monomer sodium 2-acrylamido-2-methylpropane sulfate (AMPS-Na⁺) and 2-vinyl-4, 6-diamino-1, 3, 5-triazine (VDT) and applied for Cu(II) adsorption in aqueous solutions. The hydrogel was characterized for swelling performance, surface morphology, functional groups, thermal gravimetric behavior, and elements. The maximum Cu(II) adsorption capacity (175.75 mg/g) was relatively high compared with other hydrogels. The P(AMPS-co-VDT) hydrogel also was found to have a relatively good Cu(II) desorption and reuse behavior. The adsorption mechanism could be chelation and ion exchange. This work provides a new hydrogel for effective Cu(II) removal in the future.

World over, the instances where polluters are made to pay for the damages they have caused to the environment are on the rise. If more than one party is found responsible for pollution, our analyses of statutes of different countries, covering more than 57% of the world population and more than 45% of its land area, showed that liability is to be allocated among the involved parties on an equitable basis, often decided by the courts. Analyses of a number of court cases showed that the factors considered for allocation in such cases may be classified into two, technical and non-technical. It was also found that the legal liability of pollution was different from the technical liability in many cases due to the influence of non-technical factors that were very specific to the case. These non-technical factors often do not fall under the investigation purview of an environmental forensic expert who carries out technical investigations to find the responsible parties. Based on the analysis, it is suggested that the liability allocation be a two-stage process; the first stage being technical liability allocation done by the forensic expert and the second stage the final (legal) allocation by the court. It is also suggested that clear guidelines be prepared for technical liability allocation. There was also a felt need to quantify remediability to make the remediation liability allocation easier.

There is limited information on the effect of characteristics of soil in the arid regions on the transport of pollutants. Al-Qurain landfill site is located about 1.5 km from the Arabian Gulf shoreline in Kuwait. The site was operated as an open dump and was designed without a liner or leachate collection system. This study was performed after 35 years of the site closure to investigate the quality of soil, leachate, and groundwater in its vicinity. A total of 25 test boreholes and 17 observation wells were used for the investigation. Analysis of soil, leachate, and groundwater samples shows high concentrations of organics (COD), nutrients (nitrogen, phosphorus), heavy metals, and minerals. Aging of the landfill has its impact on performance of landfill which was reflected on the characteristics of soil, leachate, and groundwater. The principal pollutants in leachate were COD, ammonia, and heavy metals as landfill age increased. A good indicator of landfill aging was the very low (0.04) BOD/COD ratio and BOD decay rate constant of 0.027/year. Water samples were also heavily polluted and their organic content ranged between 9 and 255 mg/L as BOD and 38 and 15,052 mg/L as COD. Solids levels in the water samples from the observation wells were generally higher than those typically reported in groundwater. The results showed that the mobility of the heavy metal was largely element-dependent. The organic content of the landfill played an important role in such mobility. This suggests segregation of waste disposed in landfills and replacing the open dumps by sanitary landfills to avoid such high long-term pollution that affects the site rehabilitation plans.

The most important effect of natural organic materials in water is reacting with disinfectants and creating disinfectant by-products that are mostly carcinogenic. The aim of this study was to determine the optimum conditions for removal of humic acid (HA) by zeolite coated with nZVI nanoparticles (Zeolite/nZVI) from aqueous solutions. In this study, after synthesis of zeolite/nZVI, its structure and morphology were examined using FTIR, BET, XRF, and FESEM techniques. The effects of HA concentration, composite content, pH, and reaction time were evaluated. The experimental data were analyzed by Langmuir and Freundlich isotherm and pseudo-first-order and second-order kinetic models. Finally, the thermodynamic parameters of enthalpy (ΔΗ°), entropy (ΔS°), and Gibbs free energy (ΔG°) were calculated. The results of the analyses confirmed the accuracy of the composite structure. Its specific surface area by using BET method was 203.43 m²/g. The HA removal efficiency was obtained at 92.98% in optimum conditions of 50 mg/L concentration, 2 g/L composite dose, pH = 3, and reaction time of 60 min. The results of the isotherm and kinetic study showed that the HA adsorption process follows the Langmuir isotherm (R² = 0.9707) and pseudo-second-order kinetic. The maximum adsorption capacity of the composite was determined at 23.36 mg/g by Langmuir model. Thermodynamic parameters indicate that the adsorption of HA endothermic and the reaction cannot be done spontaneously. Zeolite/nZVI composite had good removal efficiency after five times of recycling. The present study showed that zeolite/nZVI can be used as an effective adsorbent for removal of HA from aqueous solutions.

In semiarid areas producing corn in the State of Paraiba (Brazil), despite the social and economic importance of this culture associated with some types of stress mainly in semiarid regions, as well as the soils of these regions, which in many cases have a low organic matter content, generally < 1.5%, limiting the viability of the crop. The correct management of organic fertilization via fertigation is a possibility to minimize water losses by evaporation. The objective was to evaluate the vegetative growth and productive parameters of corn (Poaceae) fertigated with bovine biofertilizer under irrigation levels. The experiment was carried out under field conditions, in the locality of the agroecology sector (UEPB, Catole do Rocha, Paraiba, Brazil). The treatments were distributed in blocks at random with four replications, in a 3 × 5 split plot scheme, represented by three irrigation depths (60, 90, and 120% of ETc—crop’s evapotranspiration) that when applied daily were considered the main plots and the subplots represented by the doses of biofertilizer (0, 20, 40, 60, and 80 mL plant⁻¹) applied biweekly via fertigation, totaling to 60 experimental plants. Plants on water stress conditions inhibit their growth and production, but when associated with biofertilizer, they result in plants with greater productive potential in semiarid conditions. The blade of 120% of the ETc provided greater growth and production of corn compared with the layers of 60 and 90% of the ETc. The 50 ml plant⁻¹ biofertilizer dose provided corn growth and production compatible with conventional cultivation.

Freshwater ecosystems are recognized as one of the important natural methane (CH₄) sources, but little is known about the emission hotspots and the effects of algal blooms on CH₄ production in deep lakes. In this study, carried out from the littoral (S1), pelagic (S2-S4), and the deepest site (S5), water samples from different depths and sediment cores were collected along the transect of Lake Fuxian, a deep monomictic lake to investigate the spatial–temporal variations of CH₄. Dissolved methane concentration observed at the oxic metalimnion was 37.5% and 19.5% higher than that those observed at the epilimnion and at the layer between 80 and 100 m depth, respectively. During the overturn period, the vertical distribution of CH₄ in the water column was uniform, with an average concentration of 0.031 ± 0.007 μM in S2–S5. Statistical analysis indicated that the CH₄ concentration in the water column was significantly higher in S1 than other sites along the transect during both sampling periods. Sediment CH₄ concentration and methane production potential (MPP) were also significantly higher in S1 than in other sites. Along the sediment depth, the maximum MPP was observed at 6–8 cm in S1, but it moved up to the surface layer in S2–S5 in both sampling periods. In addition, stable carbon isotope analysis indicated that the surface sediments in the pelagic zone (S2–S5) mainly comprised autochthonous organic matters. In this zone, MPP had a significantly positive correlation with sediment total organic carbon (TOC) (R² = 0.401, p < 0.01). In summary, we described the spatial and temporal distributions of CH₄ in deep Lake Fuxian, littoral zones are CH₄ emission hotspots that can contribute to the CH₄ accumulation in the oxic metalimnion layer during the stratification period. In the pelagic zone, autochthonous organic matter was transported into the surface sediment after a massive algal bloom, representing another hotspot for CH₄ production.

The rapid development of industrial sector has increased the heavy metal pollution issue recently, as the need of various metals is increasing for manufacturing purpose. These metals are the natural components that can be found in soil, but contamination happens when the concentration of these metals are high in soil due to anthropogenic activities. Several remediation techniques such as physical method, thermal desorption, chemical, and electrokinetic remediation are used to remediate the soil contaminated by heavy metals recently. As these remediation technologies have limitation on cost, effectiveness, and environmental friendly remediation issue, phytoremediation is then attracting the attention from various researchers due to its advantages of efficient, cost-effective, and eco-friendly remediation method. The mechanisms of phytoremediation are phytoextraction, phytostabilization, phytovolatilization, phytodegradation, phytodesalination, rhizofiltration, rhizodegradation, and phytoevaporation. However, these mechanisms were affected by several factors such as the plant species, properties of medium, bioavailability of metal, and the addition of chelating agent. The type of plant utilized for phytoremediation (metallophytes) is categorized as metal indicators, metal excluders, and metal hyperaccumulators. This review article comprehensively discusses the source and effect of heavy metal on human health as well as phytoremediation techniques and mechanism during the heavy metal removal.

The asymmetrical impacts of globalization and tourism on pollution emissions of 5 South Asian countries for the period from 1980 to 2018 are examined through a non-linear autoregressive distributed lag (NARDL) technique, which shows that both short and long-run coefficients are asymmetric. The findings suggest that positive and negative shocks in globalization affect carbon emissions differently in the case of Bangladesh, India, and Pakistan, while similar results are found in the case of Nepal and Sri Lanka in the long run. Furthermore, positive tourism shock, in the long run, ameliorates the environmental quality by reducing carbon emissions in Nepal and Sri Lanka, however, increases the carbon emissions in Bangladesh, India, and Pakistan. While negative tourism shock has an adverse effect on positive shock on carbon emissions in South Asia. The phenomena of globalization and tourism can exert a severe impact in aggravating the pollution emissions that policymakers should forecast and oppose. Based on these findings, some policy suggestions are proposed for South Asian economies.

Liquid effluents from various dyeing industries often have a high concentration of dyes that diffuse into river systems and can be toxic and non-degradable in the environment. In this study, the potential of the use of timbaúva seed husks in the preparation of four adsorbents tested in the removal of methylene blue was analyzed: in natura, chemically activated material (qₘₐₓ = 1.24 ± 0.04 mg g⁻¹), carbonized (qₘₐₓ = 1.96 ± 0.03 mg g⁻¹), and activated carbon (qₘₐₓ = 1.983 ± 0.04 mg g⁻¹). The adsorbents were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and CHN elemental analysis to assist in the proposed dye adsorption mechanism in the adsorbents tested. In the adjustment of the kinetic parameters, the pseudo-second order model was predominant by the statistical analysis of the ARE and R². The carbonized samples were better adjusted to Langmuir isotherms. The removal efficiency of the methylene blue dye in aqueous solutions at the concentrations and conditions studied was 86.78%. The coal from the seed husks of timbaúva has shown excellent performance in adsorption of the methylene blue dye and, therefore, can have technological application.

The coal-to-electricity project (CTEP) using electricity instead of coal for heating is a significant measure to cope with climate change and air pollution in China. After years of development, the CTEP has been implemented on a large scale of areas in Beijing. An evaluation model is proposed in this paper to analyze the environmental benefits and assist in determining whether the CTEP should be continued. Firstly, the heating system and framework of this paper are introduced. We also analyzed the feasibility of CTEP, illuminating how electric heating benefits the environment. Secondly, the evaluations models of CTEP are built, including reduction of coal, pollutant emission, and overall benefit. Finally, based on the models results are obtained and discussed and prove environmental benefits of CTEP. It is calculated that 18 kg of coal per unit heating area can be saved in the CTEP, which effectively reduces 98% of PM2.5, 95% of SO₂, 44% of NOX, and 81% of CO₂ emissions. The CTEP has increasing contribution to the reductions of atmospheric pollutants. The considerable environmental benefits demonstrate the significance of the CTEP in the north of China, which also facilitate its future development in areas outside of Beijing.