Phosphorus removal from wastewater is very important in order to prevent water eutrophication. Although there are many ways to remove phosphorus, electrocoagulation (EC) is a promising method. However, the efficiency of conventional EC processes needs to be further improved. In this study, magnetized iron particle anodes used for EC were fabricated and batch experiments were conducted. The results showed that magnetized anode configuration (iron powder, iron filings, iron sheet), current density (i), as well as electrolysis time had significant effects on phosphorus removal. Particle electrodes (e.g., iron powder) with both large specific surface area and high current density were beneficial for phosphorus removal. Simultaneously, anode magnetization could also enhance the phosphorus removal to some extent based on the effect of magnetic field (MF) on water characteristics (e.g., conductivity). Combining the advantages of particle electrode and MF, magnetized particle anode was superior to other electrodes in phosphorus removal and cell voltage maintenance. Compared with the conventional plate anode, the magnetized iron particle anode was more economical and could reduce operating cost by more than 50%. The results are useful for the practical application of phosphorus removal by EC.

Nanoscale zero-valent iron–supported zeolite Na-P1 (Z-NZVI) was synthesized and technologically promoted for selenate (Se⁶⁺) removal from water. NZVI, Z, and Z-NZVI were characterized using XRD, FTIR, high-resolution transmission electron microscopy with energy-dispersive X-ray spectroscopy (HR-TEM-EDS), and XANES techniques. Morphology and visualizing analysis using HR-TEM-EDS demonstrated that NZVI was uniformly distributed on the surfaces of Z in the Z-NZVI sample, which apparently reduced the aggregation of NZVI and would thereby increase the reduction activity. The Z-NZVI demonstrated higher efficiency for Se⁶⁺ removal since the high synergistic effect of Se⁶⁺ reduction and sorption by Z-NZVI. XANES analysis indicated that Z-NZVI could enhance Se⁶⁺ reduction into and selenium (Se⁰), while the adsorption phenomenon emerged on the Z-NZVI surface. Z performed as a supporter of the insoluble products, improving the reduction activity of NZVI. The high capacity of Z-NZVI provides promising technology for the removal of selenium from aqueous solutions.

It is globally acceptable that carbon dioxide (CO₂) emissions are one of the greenhouse gases are considered the main factor influencing global warming and environmental degradation. The present study focuses on China, the world’s largest carbon emitter. The study aims to capture the time-frequency dependency of economic growth and CO₂ emissions in China for the time period 1950–2016 using a wavelet coherence approach, which allows us to investigate both the long-run and short-run causal links of the estimated variables. In order to capture the long-run and causal linkage between economic growth and CO₂ emissions, the study employs Maki cointegration, wavelet coherence, Toda-Yamamoto causality, Fourier Toda-Yamamoto causality, and nonparametric Granger causality tests. The findings of this study reveal that (i) there is a significant vulnerability between economic growth and CO₂ emissions throughout the 2000s both the short-term and medium-term; (ii) there is long-run cointegration linkage between economic growth and CO₂ emissions in China; (iii) economic growth in China has an important power for predicting CO₂ emissions over the selected study period, especially in the short-term and medium-term; and (iv) it was observed that there is positive correlation between economic growth during the 1980s and 1990s in the short-term only. The outcome of the Toda-Yamamoto causality, Fourier Toda-Yamamoto causality, and nonparametric Granger causality tests underlines that economic growth is a robust policy variable for predicting CO₂ emissions in China.

To understand the potential risks of heavy metals, including their bioavailability and toxicity, 15 surface sediment samples were collected from Luhun Reservoir in Luoyang city, China. Total concentrations and chemical fractions of Cd, Cr, Cu, Ni, Pb, and Zn were analyzed. Various rating methods were used to evaluate the degree, risk, and toxicity of the heavy metal pollution. Results showed that Cd and Pb were preferentially associated with exchangeable (55.77–69.76%) and reducible (53.54–69.43%) fractions, respectively, and therefore exhibited high potential availability. Cr (57.14–86.56%) and Ni (32.21–72.77%) occurred primarily in the residual fraction. Metal concentrations in the effective fraction of the sediment decreased in the order: Cd (96.32%) > Pb (91.61%) > Cu (64.54%) > Zn (57.23%) > Ni (41.51%) > Cr (21.68%). Risk assessment indicated that the risk for Cd is extremely high (62.96%); Cu, Pb, and Zn are ranked as medium risk. Based on the potential ecological risk index, these metals (especially Cd) showed higher potential risk near the dam region. Toxic unit values (2.89–6.05) in more than 60% of sediment sites exceeded a value of 4, and Pb had a relatively higher contribution (1.06–2.65). Cd and Pb are the main contaminants in sediments of Luhun Reservoir and should be paid more attention in the future.

Climate change is occurring and is influencing biological systems through augmented temperatures, more inconstant precipitation, and rising CO₂ in the atmosphere. For sustainable landscaping, it was essential to assess the diversity of native/wild grasses and their suitability for turf and to combat the salinity problem in the region. For this purpose, a native halophytic grass, Aeluropus lagopoides, was investigated by conducting mowing tests on its ecotypes during the year 2014–2016 under desert climatic conditions. The research was carried out in two phases, i.e. Phase-I was for collection and establishment of ecotypes from various parts of UAE, while in Phase-II, mowing tests were conducted. During mowing tests, 50 ecotypes of A. lagopoides were given various mowing treatments (i.e. they were cut back at 1-, 2-, 3-, 4- and 5-cm heights) in field conditions. Significant differences were found among various ecotypes for different agronomic parameters such as ground cover, canopy stiffness, leaf number, clippings fresh and dry weights and internode length. Overall, the grass exhibited better performance at mowing heights of 3 and 4 cm, which are the standard mowing heights for turfgrasses. Ecotypes FA5, RA3, RUDA2, RUDA7 and RUADA1 of A. lagopoides showed the best performance against mowing shock and became the candidates for the turfgrass varieties from the native Arabian flora.

In this study, a new reuse process of the coarse fraction of basic oxygen furnace (BOF) sludge based on iron recovery by the ferrous sulfate production was proposed. This study was based on three main steps: (i) characterization of the steel waste, (ii) evaluation and optimization of the recycling process, and (iii) characterization of ferrous sulfate produced. Acid leaching was used to solubilize the iron for obtaining ferrous sulfate heptahydrate. The ferrous sulfate crystallization was performed by adding anhydrous ethanol (EtOH). A multivariate optimization for iron leaching and ferrous sulfate precipitation in the same solution was employed. This optimization consisted of screening steps using a full factorial design followed by optimization. The coarse fraction of BOF sludge was predominantly composed of iron in metallic form (82.5%, dry weight). The sulfuric acid concentration and leaching time had significant effects on Fe(II) solubilization. The desirability function predicted the following optimized conditions: 20% (v/v) sulfuric acid solution, 200 min of leaching time, 7.00 g of waste, and 110 mL of anhydrous EtOH, producing 19.60 g of ferrous sulfate heptahydrate (yield of 70.8%). The characterization of ferrous sulfate was performed by X-ray diffraction, scanning electron microscopy coupled to energy-dispersive X-ray spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. The characterization of the ferrous sulfate produced evidenced the effectiveness of the optimized process condition. Graphical abstract

For the first time, the National Health and Nutrition Examination Survey (NHANES) released data on hemoglobin adducts of formaldehyde (HCHO) in public domain for US children aged 6–11 years, adolescents aged 12–19 years, and adults aged > = 20 years for 2015–2016. This study was undertaken to evaluate the associations between concentrations of HCHO in whole blood and smoking, exposure to environmental tobacco smoke (ETS), and self-reported diagnoses of cancers and asthma. Adult smokers were found to have higher adjusted concentrations of HCHO than nonsmokers (127.7 vs. 125.1 pmol/g Hb, p = 0.02). Exposure to ETS was not found to affect the adjusted concentrations of HCHO. No associations were observed between HCHO concentrations and self-reported diagnosis of “ever” cancer as well as self-reported presence of asthma at the time of participation in NHANES. HCHO concentrations were not found to differ across genders and racial/ethnic groups for children and adolescents. Among adults, non-Hispanic blacks (120.0 pmol/g Hb) had lower adjusted concentrations (p < = 0.01) of HCHO than non-Hispanic whites (128.8 pmol/g Hb), Mexican Americans (129.4 pmol/g Hb), other Hispanics (130.3 pmol/g Hb), and non-Hispanic Asians (127.9 pmol/g Hb). In conclusion, self-reported diagnoses of cancer and asthma were not found to be associated with observed concentrations of HCHO in whole blood.

The objective of this study is to examine the relationship between corporate social performance (CSP) as proxy of corporate social responsibility (CSR) and corporate firm’s performance (CFP) in the context of Pakistani financial and non-financial firms sectors. This study comprises two main firm’s performance indicators such as market base (excess stock returns) and accounting base (returns on assets and returns on capital). The data set starts from 2011 to 2017 and consists of three hundred and fifty (350) firms on equal numbers of financial and non-financial firms. This study uses a non-linear and disaggregated approach for data analysis. The results of the linear model indicate that CSP and returns on capital have a negative relationship, while the non-linear model of CSP and accounting base performance as CFP have positive association in the domain of long run. There is a significant relationship that exist among environmental social governance (ESG) disclosure score, government sub-components score, and social performance. However, a U-shaped association found between CFP and government sub-components, which further suggest that governance has a vital role toward CSP and CFP components.

Shale reservoirs are one of the unconventional reservoirs that a large volume of hydrocarbon reserves have remained in these reservoirs. Thereby, proper measurement of reservoir characteristics will help to provide an economical and efficient required water as water scarcity has always been a significant challenge throughout recent decades. In this study, eight different production wells in the same formation were selected to consider the required freshwater and reused water for each well as a comparative analysis. According to the results of this study, the percentage of saved water from hydraulic fracturing flow-back water is approximately 85%. Therefore, it only needs 15% of freshwater to continue fracturing process each day, and photo-Fenton and floatation would be an excellent method to remove solids and chemicals from flow-back water. Furthermore, the percentage of saved water from water flooding processes and chemical enhanced oil recovery methods is approximately 70% and 75%, respectively. Therefore, it only needs 30% and 25% of freshwater to continue water flooding processes and chemical enhanced oil recovery methods each day. The approximate total volume of annual saved water is 104 MM m³ in which 1000 inhabitants could be still alive, and it will not be necessary to use the extreme volume of sweet water for hydrocarbon production.

To promote the application of microbially induced mineralization technology in the field of coal dust suppression, two urease-producing bacteria were co-cultured, with the aim to define the influence of different culture conditions on the growth and urease activity of the bacteria. According to the results, when S. pasteurii and B. cereus CS1 were inoculated in succession at a volume ratio of 1:1 and an interval of 14 h, the mixed bacteria achieved optimal growth and had the highest urease activity; when the initial pH value of culture medium was 9 and the urea and Ca²⁺ concentrations in the substrate were uniformly 0.1 mol/L, the growth and urease activity of the mixed bacterial culture reached their peaks. SEM-EDS and XRD results indicated that, regardless of the specific urease-producing bacteria used (single urease-producing bacteria or the mixed urease-producing bacteria), their mineralization products were uniformly vaterite-type and calcite-type calcium carbonate; FTIR and thermogravimetric analysis also confirmed their mineralization products as calcium carbonate. By spraying the bacterial inoculants with a corresponding calcium source and urea on pulverized coal, it was found that the bacteria successfully survived and caused pulverized coal to be consolidated. In particular, the mixed bacterial inoculant manifested a stronger consolidation effect, with a wind erosion–induced mass loss of less than 20 g/(m²•h). We provide experimental support for the field of microbial coal dust suppression.