The present study aims at enhancing the yield of tubular solar still (TSS) by employing fins and coating the absorber plate. We doped the SiO₂ nanoparticles into black paint at the weight concentration ranging from 10 to 40%. The solar still was tested in a bright sunny climatic condition of Chennai, Indian (lat. 13° 08′ N and long. 80° 27′ E). Under transient heat flux conditions, water, basin, and TSS glass temperatures with and without fin were measured. The rate of heat transfer by convection between the water and absorber plate was increased. Results revealed that the basin and water temperatures were improved by 10.49% and 10.88%, respectively when using black paint with SiO₂ nanoparticle in the concentration of 20%, coated on the absorber plate compared to that when using the ordinary black paint, while using the fins on the absorber plate enhanced the potable water produced by 55.18% when using 20% SiO₂ nanoparticle compared to that of conventional TSS. The cost per liter of water produced using the flat and finned absorber coated using 20% SiO2 nanoparticle in black paint is found as 0.0187 and 0.012 $/L respectively.

Remediation materials are the most critical factors for in situ immobilization of soil contaminated by heavy metals. In this study, in order to improve the performance of palygorskite (Pal), a new remediation material, mercapto-grafted palygorskite (MPal) was synthesized by grafting mercapto groups onto the surface of Pal. The results of field application in northern China showed that at a dosage of 0.12–0.23 kg m⁻², MPal significantly reduced the available concentrations of Cd, Pb, and Cr in the soil by 52.2%, 29.9%, and 46.2%, respectively. Concurrently, Cd, Pb, and Cr concentrations in the shoots of head lettuce also decreased significantly, with the highest reduction being 44.0%, 61.5%, and 50.0%, respectively. At the same dosage, MPal had a better immobilization effect than Pal. There was no significant change in the pH of the vegetable soil, while the zeta potential decreased significantly, indicating that the MPal did not immobilize the heavy metals by increasing the pH, making it suitable for alkaline farmland soil. In addition, soil environmental quality was improved overall. MPal increased the activities of urease, β-glucosidase, cellulase, and catalase by 15.4%, 56.5%, 7.8%, and 14.9%, respectively. It increased the number of fungi and actinomycetes by 4.5% and 23.1%, respectively. MPal, as a new remediation material for soil contaminated by heavy metals, could achieve efficient remediation effects when applied in small doses. Compared with Pal, it is environmentally friendly, is low cost, and is more suitable for the treatment of heavy metal pollution in large areas of farmland.

This study presented the efficient removal of tartrazine, a typical biorefractory dye, in a heterogeneous photochemical Fenton-like system adopting Fe⁰ and oxalate (Ox) (UV/Fe⁰/Ox). Only 47.4% tartrazine could be removed within 60 min with a UV/Fe⁰ system. The addition of Ox could significantly enhance the removal of tartrazine to 72.4% within only 20 min with the UV/Fe⁰/Ox system. The effects of various factors, such as the Fe⁰ dose (0–0.8 g/L), Ox dose (0–2 mM), initial pH (2–6), and initial tartrazine concentration (2–30 mg/L), on the removal of tartrazine were examined. Scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and Mossbauer spectroscopy were conducted to explore the mechanism by which oxalate enhances the performance of the UV/Fe⁰ system. Ox could inhibit the formation of iron (hydro)xides on the Fe⁰ surface, thus guaranteeing the reactivity of Fe⁰ during the reaction. Compared with Fe₂O₃, FeS, and Fe₃O₄, Fe⁰ was a good heterogeneous iron catalyst for the photolysis of tartrazine with the Ox system. Compared with H₃PO₄, nitrilotriacetic acid, and ethylenediaminetetraacetic acid, Ox was also a good photolysis chelating agent. The UV/Fe⁰/Ox system could also maintain fast tartrazine removal after five consecutive runs without the addition of Fe⁰, indicating the good stability of Fe⁰.

Nickel (Ni) in small plateau lake sediments plays an important role in influencing the quality of lake ecosystems with a high degree of endemism and toxicity. This paper focuses on the spatial distribution and ecological risks of nickel in the sediments of Jianhu Lake, a small plateau lake in China, and the influence of pH and total organic carbon (TOC) on nickel concentrations. The results showed that average total nickel concentrations were 138.99 ± 57.57 mg/kg (n = 38) and 184.31 ± 92.12 mg/kg (n = 60) in surface sediments (0–10 cm top layer) and sediment cores (0–75 cm depth), respectively, and that the residual fraction was the main form of nickel. Simultaneously, through a semivariogram model, strong spatial dependence among pH, TOC, and the oxidizable fraction was revealed, whereas total nickel, exchangeable and the weak acid soluble fraction, reducible fraction, and residual fraction showed moderate spatial dependence. The vertical distribution revealed that nickel accumulated mainly in the bottom 5 cm (70-75 cm) of the sediment layer and that the pH was higher there, whereas TOC was concentrated mainly in the top 5 cm of sediment. Using geoaccumulation and a potential ecological risk index, moderate nickel pollution and moderate risk levels were found in most surface sediments, but moderate nickel pollution and high risk levels were observed in most sediment cores. In addition, pH and TOC were found to have a strong effect on the distribution and concentration of nickel and its fractions in the small plateau lake. In summary, nickel posed a certain degree of pollution and ecological risk, which deserves attention in the sediments of small plateau lakes.

The COVID-19 pandemic is one of the contagious diseases involving all the world in 2019–2020. Also, all people are concerned about the future of this catastrophe and how the continuous outbreak can be prevented. Some countries are not successful in controlling the outbreak; therefore, the incidence is observed in several peaks. In this paper, firstly single-peak SIR models are used for historical data. Regarding the SIR model, the termination time of the outbreak should have been in early June 2020. However, several peaks invalidate the results of single-peak models. Therefore, we should present a model to support pandemics with several extrema. In this paper, we presented the generalized logistic growth model (GLM) to estimate sub-epidemic waves of the COVID-19 outbreak in Iran. Therefore, the presented model simulated scenarios of two, three, and four waves in the observed incidence. In the second part of the paper, we assessed travel-related risk in inter-provincial travels in Iran. Moreover, the results of travel-related risk show that typical travel between Tehran and other sites exposed Isfahan, Gilan, Mazandaran, and West Azerbaijan in the higher risk of infection greater than 100 people per day. Therefore, controlling this movement can prevent great numbers of infection, remarkably.

In this work, a new attempt was made to study the behavior of the conventional solar still (CSS) by adding a black-painted copper plate and phosphate pellets. Therefore, the performance of the three solar stills has been studied and compared. The first is the CSS, and the second is the modified solar still (MSS). The MSS performance was tested using black-coated copper plate (measuring 49 × 49 cm and 0.2 cm thick) with and without phosphate pellets and compared to the CSS in the similar climatic conditions. The results showed that the combination of black coated copper plate and the inclusion of phosphate pellets improved the evaporation rate and daily productivity. During the experiments, yields using black coated copper plate without and with phosphate pellets were 14.96% and 29.53% greater than the CSS. The effectiveness of the CSS, MSS with copper metal plate (MSS-CP), and MSS with copper metal plate with phosphate pellets (MSS-CP and PP) are around 30.23, 35.3, and 41.44%, respectively.

Hydrocarbon is a primary source of energy in the current urbanized society. Considering the increasing demand, worldwide oil productions are declining due to maturity of oil fields and because of difficulty in discovering new oil fields to substitute the exploited ones. To meet current and future energy demands, further exploitation of oil resources is highly required. Microorganisms inhabiting in these areas exhibit highly diverse catabolic activities to degrade, transform, or accumulate various hydrocarbons. Enrichment of hydrocarbon-utilizing bacteria in oil basin is caused by continuous long duration and low molecular weight hydrocarbon microseepage which plays a very important role as an indicator for petroleum prospecting. The important microbial metabolic processes in most of the oil reservoir are sulfate reduction, fermentation, acetogenesis, methanogenesis, NO₃⁻ reduction, and Fe (III) and Mn (IV) reduction. The microorganisms residing in these sites have critical control on petroleum composition, recovery, and production methods. Physical characteristics of heavy oil are altered by microbial biotransformation and biosurfactant production. Considering oil to be one of the most vital energy resources, it is important to have a comprehensive understanding of petroleum microbiology. This manuscript reviews the recent research work referring to the diversity of bacteria in oil field and reservoir sites and their applications for enhancing oil transformation in the target reservoir and geomicrobial prospecting scope for petroleum exploration.

Increasing business organizations are also damaging the natural infrastructure, and researchers are pressing hard on this issue since several decades. Moreover, the studies relating to business organizations only focus on the establishment, development, and success of businesses and paid less attention to the dark trade business expansions, i.e., lack of green innovation and increase in pollution and environment damages. Keeping in view these issues, this study is aimed at investigating the effect of green dynamic capabilities, green practices, and green value co-creation on green innovation in SMEs (small and medium enterprises). This study also tested the mediating role of value co-creation in the links between green practices-green innovation and green dynamic capability-green innovation. Structural equation modeling (SEM) was used, and the mediation analysis was conducted through Preacher and Hayes Approach (2004, 2008) and through Soble test. Empirical results proved that green dynamic capabilities, green practices, and green value co-creation improve the mechanism of green innovation in SMEs.

Forests within major cities, such as Table Mountains, Afromontane forests, are constantly subjected to industrial and urban pollution sources. Cape Town is one of the most profound areas in the world for plant extinction and already has a high occurrence of threatened species. The objective of this study was to determine the concentrations of the metals, aluminium and iron, commonly emitted from anthropogenic activities in key forest organisms (mosses, lichens and millipedes), soil and leaf litter in three forests (Platbos, Orange Kloof and Newlands) in the Western Cape, South Africa. In general, the metal concentrations increased with traffic volumes and traffic behaviour (frequent braking and acceleration). Factors, such as the locations of the sites and forests, wind and different accumulation abilities of bioindicators had a notable impact, as did the natural geological origin of aluminium and iron. Of significance in this study was the metal contamination in forests in close proximity of the centre of the city Cape Town.

A growing literature indicates that untreated wastewater from leaky sewers stands among major sources of pollution to water resources of urban systems. Despite that, the quantification and allocation of sewer exfiltration are often restricted to major pipe areas where inspection data are available. In large-scale urban models, the emission from sewer exfiltration is either neglected (particularly from private sewers) or represented by simplified fixed values, and as such its contribution to the overall urban emission remains questionable. This study proposes an extended model framework which incorporates sewer exfiltration pathway in the catchment model for a better justified pollution control and management of urban systems at a nationwide scale. Nutrient emission from urban areas is quantified by means of the Modelling of Nutrient Emissions in River Systems (MONERIS) model. Exfiltration is estimated for public and private sewers of different age groups in Germany using the verified methods at local to city scales, upscaling techniques, and expert knowledge. Results of this study suggest that the average exfiltration rate is likely to be less than 0.01 L/s per km, corresponding to approximately 1 mm/m/year of wastewater discharge to groundwater. Considering the source and age factors, the highest rate of exfiltration is defined in regions with significant proportions of public sewers older than 40 years. In regions where public sewers are mostly built after 1981, the leakage from private sewers can be up two times higher than such from public sewers. Overall, sewer exfiltration accounts for 9.8% and 17.2% of nitrate and phosphate loads from urban systems emitted to the environment, which increases to 11.2% and 19.5% in the case of no remediation scenario of projected defective sewer increases due to ageing effects. Our results provide a first harmonized quantification of potential leakage losses in urban wastewater systems at the nationwide scale and reveal the importance of rehabilitation planning of ageing sewer pipes in public and private sewer systems. The proposed model framework, which incorporates important factors for urban sewer managers, will allow further targeting the important data need for validating the approach at the regional and local scales in order to support better strategies for the long-term nutrient pollution control of large urban wastewater systems.