Rapid population growth and industrialization have contributed to a dramatic decline in the supply of freshwater. As a result, desalination is an important choice to solve the global problem of water scarcity. Nevertheless, the hyper-saline by-product, the high capital costs, and the high energy demands currently met by fossil fuels are key obstacles to the widespread adoption of desalination systems. Furthermore, desalination plants powered by fossil fuels have negative environmental impacts due to greenhouse gases (GHGs) emissions. In contrast to fossil fuels, renewable energy is abundant and clean and is therefore a promising alternative for powering desalination plants. This is why the water-energy nexus is a crucial step towards a sustainable future. Therefore, the integration of renewable energy sources (RES) into desalination is very important. The main objective of this review to analyze and evaluate desalination technologies (thermal-based and membrane-based) and RES (solar, wind, hydropower, geothermal, and biomass) that could be combined as an integrated process. Social-economic factors, environmental concerns, current challenges, and future research areas for both desalination and RES are discussed.

Microzooplankton is an important component in the plankton food web transferring microbial food web carbon to the higher trophic levels, including fishes. This study investigates the role and significance of microzooplankton in the diet of three economically important small pelagic fishes along the southwest coast of India: Indian oil sardine (Sardinella longiceps), Indian mackerel (Rastrelliger kanagurta) and Commerson’s anchovy (Stolephorous commersoni). The diet content of oil sardine was dominated by diatoms throughout the year with an increase in the presence of microzooplankton and copepods during the Northeast Monsoon. Phytoplankton, microzooplankton and copepods represented the diet of Indian mackerel throughout the year. Commerson’s anchovy differed considerably in their diet composition from both Indian oil sardine and Indian mackerel as they chiefly depended on a carnivorous diet feeding on copepods, fish eggs, ostracods, lucifers and microzooplankton. The present study concludes that organic carbon from the microbial food web also, through microzooplankton, provides nutritional support to small pelagic fishes along the southwest coast of India but in varying degrees depending on the fish species as well the seasons.

The anthropogenic carbon dioxide (CO₂) denseness in the earth’s atmosphere is increasing day-to-day by combusting fossil fuels for power generation. And, it is the most important greenhouse gas (GHG) responsible for 64% of global warming. Solvent-based carbon capture gained more attention towards researchers because of its easiness to integrate with the coal-fired power plant without significant modifications. During CO₂ absorption, the physical property of the solvent gets changed. A change in the solvent’s physicochemical property affects further CO₂ absorption, thereby increasing the carbon-capture energy demand. The present experimental study encompasses CO₂ absorption studies using 30 wt% aqueous monoethanolamine (MEA), 2-amino-2-methyl-1-propanol (AMP) and piperazine (PZ) followed by the detailed analysis of physicochemical properties (pH, carbon loading (α), viscosity (μ), density (ρ) and surface tension (σ)) of various CO₂-loaded solutions. The results revealed that these properties are exhibiting interdependent eccentrics. Furthermore, an empirical model was developed to predict the carbon loading of the tested solvents. This model includes the tested physicochemical properties, reaction mixture temperature, diffusivity and change in the mass of solvent during carbon loading. In addition, an empirical model for viscosity as a function of temperature, carbon loading and molecular weight of solvents was developed. These models appear to predict the carbon loading and the viscosity well with greater accuracy. Graphical abstract

Selenium (Se), iron (Fe), and humic acid (HA) are beneficial fertilizers that inhibit cadmium (Cd) uptake in crops and are crucial for agricultural yields as well as human health. However, the joined effect of Se, Fe, and HA on Cd uptake in rice are still poorly understood. Therefore, a hydroponic culture experiment was established to evaluate the combined effect of Se (Se⁴⁺ or Se⁶⁺), Fe, and HA on the biomass, Cd uptake, and Cd translocation of/in rice seedlings. Compared to Se⁶⁺ application, Se⁴⁺ application in most treatments resulted in lower Cd translocations from roots to shoots, leading to a significant decrease in shoot Cd concentrations. Compared to the treatments with Se⁴⁺ or Fe²⁺ application, joined application of Se⁴⁺ and Fe²⁺ inhibited Cd uptake in shoots by decreasing Cd adsorption onto (iron plaque) and uptake by roots, and alleviating Cd translocation from root to shoot. Compared to the treatments with Se⁶⁺ or Fe²⁺ application, joined application of Se⁶⁺ and Fe²⁺ inhibited Cd uptake in shoots by sequestering (retaining) Cd onto root surface (iron plaque). HA inhibited Cd uptake in all treatments by decreasing the bioavailability of Cd in the nutrient solution through complexation. The simultaneous application of Se, Fe, and HA decreased the shoot Cd concentrations the most, followed by the combined application of two fertilizers and their individual application; the mean shoot Cd concentration in the Fe-SeIV-HA2 treatment was the lowest among all the treatments, at only 11.39 % of those in the control treatments. The 3-way ANOVA results indicated that the Cd concentrations in shoots were significantly affected by Se, Fe, HA, and certain of their interactions (Fe×Se and Se×HA) (p< 0.05). The above findings suggest that the joined application of Se, Fe, and HA ameliorated Cd uptake mainly by inhibiting Cd adsorption onto (iron plaque) and uptake by roots and the translocation from roots to shoots (Fe×Se⁴⁺), retaining (sequestering) Cd in iron plaque (Fe×Se⁶⁺), and decreasing Cd availability in nutrient solution (HA).

Biomass waste contributes 14% of the total global energy. And 15–20% of the coal-fine waste from coal mines are deposited in the rivers, ponds, etc., unused, which leads to resource wastage and environmental pollution. The present study aims utilizing biomass and coal-fine waste for producing biomass-coal briquettes without using a binding material. Three different average sizes 50, 134.3, and 199.7 μm of biomass mixture (bagasse, groundnut shell, and woodchips) and coal-fines were used to make different ratios of biomass and coal mixture briquettes. Then, it is subjected to proximate, scanning electron microscope/elemental (SEM/EDX) and thermo-gravimetric analysis (TGA) to understand its property. Proximate analysis results revealed that the biomass waste has the low ash, sensible fixed carbon, and high volatile matter content. A briquette of biomass: coal = 7:1 ratio 50-μm particle size case was chosen for SEM/EDX and TGA analysis since it holds reasonable fixed carbon value comparatively. SEM analysis revealed irregular surfaces, cracks, cavities and longitudinal cracks, veins distribution all around, ups and shallows on the surface and it is the most favorable condition for fuel combustion since oxidant reaches the core of the fuel with less resistant. TGA reconfirms the spontaneous burning characteristics of the entire volatiles and fixed carbon. EDX analysis shows that the carbon and potassium are the two major elements present in the tested briquettes.

Heavy metal in the physical environment may alter immune function and predispose to develop asthma in human. Our study was aimed to investigate associations between urinary heavy metals and asthma in adults. A retrospective cross-sectional study was conducted with 3425 subjects aged 20 years and older in the US National Health and Nutrition Examination Survey (NHANES) 2011–2014. Binary logistic regression was applied to analyze associations between cobalt (Co), tungsten (W), and uranium (U) and asthma. We found positive associations between U and asthma (OR = 1.74, 95%CI: 1.25, 2.44, P for trend < 0.01). U was positively associated with asthma in 20–59 years group (OR = 1.65, 95%CI: 1.11, 2.46), while W and Co were related with asthma among in above 60 years group (OR = 2.39, 95%CI: 1.24, 4.58, P for trend = 0.02; OR = 1.88, 95%CI: 1.02, 3.47, respectively). U was linked with asthma in both males and females (OR = 1.93, 95%CI: 1.16, 3.20; OR = 1.59, 95%CI: 1.01, 2.51, respectively). Positive associations between U and asthma were discovered among adults with family history of asthma or not (OR = 2.15, 95%CI: 1.17, 3.95, P for trend = 0.03; OR = 1.62, 95%CI: 1.08, 2.43, P for trend = 0.03, respectively). Remarkable association was observed between U and asthma in adults without hay fever (OR = 1.79, 95%CI: 1.24, 2.60, P for trend = 0.02). Our findings provide epidemiological evidence to highlight a need to prioritize heavy metals exposure with asthma.

Although numerous studies have explored various impacts of Internet use, few have investigated the linkage between Internet use and chemical fertilizer use in developing economies. This study examines the influences of Internet use and related promotion policy on chemical fertilizer use based on a nationwide dataset including China’s 7766 rural households. The baseline regression results show that Internet use reduced chemical fertilizer use significantly. The mechanism analysis unveils the mediation role of human capital; Internet use increased farmers’ human capital and then reduced chemical fertilizer use. In addition, the difference-in-difference method is employed to examine the effects of Internet promotion policy and the findings reveal that the promotion policy could help reduce farmers’ use of chemical fertilizer. Finally, both propensity score matching-DID model and a two-stage instrumental variable model are used to address potential endogeneity issues associated with Internet use, and results indicate that the empirical results are robust. Our findings suggest that improving the availability of broadband access in a rural area, promoting Internet-related training and education, and more government’s investment in rural ICTs infrastructure can contribute to the reduction of chemical fertilizer use.

The green spaces preserve natural heritage, spectacular landscapes, and wildlife habitats. By incorporating national parks, it leads to economic growth, environmental sustainability, social involvement, and provides a protected area for endangered wildlife. Nature-dependent tourism indicates a critical place within the national economy. Pakistan is tackling the tourism industry and implementing nature-related approaches using national parks. The main objective of the proposed study is to appraise the economic value of the eastern arid regions of Pakistan and determine their environmental importance. For the assessment of recreational value, the travel cost method (TCM) and the zero truncated negative binomial regression models were chosen. Recreation demand was negatively linked to salary and had a significant positive association with the place of residence, age, and length of stay. The total estimated annual consumer surplus of the parks was Rs. 3317/person, while outsider consumer surplus was Rs. 3032/person/visit, and consumer surplus native annual value was Rs. 3289/person/visit. The results show that visitors have fewer tendencies towards the recreational site, as they are restricted to paying the entrance fee. This study contributes to environmental content reservations, such as a clean atmosphere, soil protection, and a stable ecosystem. It also improves economic valuation and sends a thought-provoking signal to native authorities to effectively manage the supervision of national parks.

Copper oxide nanoparticles (CuO NPs) are one of the most widely used materials owing to their excellent properties such as thermal and photochemical stability, superconductivity, and high electrochemical activity. Once they enter the environment, Cu²⁺ may be released in water, which alters the behavior and toxicity of CuO NPs. The present study thus investigated the dissolution of CuO NPs (40 nm) in the presence of tannic acid (TA), a model chemical of dissolved organic matter. The adsorption of TA decreased the hydrodynamic diameter of CuO NPs and increased the zeta potential of the suspension. Although the adsorption of TA on particle surface improved the dispersion of CuO NPs, their dissolution extents were all reduced at TA concentration up to 55.4 mg C L⁻¹. At pH 5, the contributions of TA complexed Cu to the overall dissolution increased up to 37.8% as a function of TA concentrations. All the findings shown above approved that the strong adsorption of TA played a dominant role in preventing the dissolution of CuO NPs.

In this study, the performance of TiO₂, ZnO, UiO-66-NH₂ and UiO-66-NH₂/TiO₂ nanoparticles was investigated. They apply as photocatalysts for the destruction of organic reactive red dye 120 (RR120) under UV light. In order to determine the optimal conditions, effects of different catalysts and initial dye concentration, H₂O₂ content and catalyst loading parameters were examined. Taguchi-designed experimental method was used to obtain optimal test conditions. The physical and chemical properties of synthetic photocatalysts were investigated by SEM, XRD, EDX, BET and DRS. SEM images show that the globular particles of titania are well placed on the surface of the metal-organic framework (MOF). XRD and EDX analyses also confirmed the presence of titania in the synthesised UiO-66-NH₂/TiO₂ photocatalyst. Optimal values of H₂O₂, pH, the amount of catalyst, the dye concentration and the type of available photocatalyst to remove the RR120 dye, were obtained by 80 μl/l, 3 mg/l, 5 mg/l and 20 mg/l, UiO-66-NH₂/TiO₂ catalyst, respectively. The required time for complete removal of RR120 dye under detection limit of 0.136 mg/l in optimal conditions was 10 min. The RR120 photocatalytic degradation followed the first-order kinetic equation according to the Langmuir–Hinshelwood model (kₐₚₚ = 0.407 min⁻¹). The result of optimisation showed the 20 wt% of the titania on MOF (UiO-66-NH₂) photocatalyst can be used in advanced oxidation processes, and it can be used as a suitable option for cleaning coloured effluent.