A hypothesis was proposed that the activated sludge was converted into hydrochar full of phenolic hydroxyl and then was made into coagulant by graft copolymerization. The results show that under the addition of HCl, the content of phenolic hydroxyl on the surface of hydrochar (SBC) under hydrothermal conditions increased sharply, up to 1.586 mmol/g, showing that HCl dosage of 0.10 g/g dᵣy ₛₗᵤdgₑ and holding time of 4 h was recommended. Under graft copolymerization with the addition of DMC, the coagulant was synthesized. Based on the analysis by FTIR, XPS, zeta potential, etc., the possible synthesis route of coagulant from SBC was that phenolic hydroxyl on SBC was activated by the initiator and then the polymerization between SBC and DMC was triggered. The optimal grafting conditions are gotten. It was named as SBCHCₗ₀.₁₀ g, ₄ ₕ-g-DMC₀.₇. The removal by SBCHCₗ₀.₁₀ g, ₄ ₕ-g-DMC₀.₇ on COD and turbidity in domestic wastewater is up to 69% and 93%, respectively. The component of COD indicated that almost all particulate COD and most of colloidal COD are removed. On the contrary, the removal on dissolved COD can be neglected. Most of NH₃-N and P is kept in the wastewater. This is in favor of subsequent reuse and biological treatment.

Biodiversity refers to genetic diversity and complex sets of communities and ecosystems. Environmental degradation can jeopardize biodiversity and decrease ecosystem service quality. Biodiversity is not an endless and free commodity, and the costs of its destruction must be taken into account. Thus, estimating the monetary value of a region’s biodiversity can help stakeholders understand its economic, social, and cultural status, and ultimately, by increasing public awareness, community demands for protection and investment are properly shaped. This study aims to estimate the monetary value of biodiversity in the Central Alborz Protected Area in Iran. This area is part of the Alborz Mountain range and the wildlife and plant species of this region have a unique biodiversity. For this purpose, the willingness to pay was estimated. In designing the Choice Experiment, five attributes including “wildlife species status,” “plant species status,” “natural landscape,” “research facilities,” and “tourism facilities” have been considered. The results showed that maintaining and improving the status of animal species and tourism conditions among respondents has a higher priority than the other three attributes. The annual value of marginal willingness to pay was 13020 Tomans per person and the conservation value of biodiversity is estimated at 23 billion Tomans. Also, the results of the simple Logit model showed that the average per capita willingness to pay the respondents to protect the region is 16,369 Tomans and the value of biodiversity protection is about 28.6 billion Tomans.

The aim of this study is to assess the importance of environmental pollution caused by microplastics and their high risks for the organisms living in water and soil ecosystems. Microplastics are one of the emerging contaminants which have been widely spread in soil and aquatic environments. In the last few years, many studies have been focused on their distribution and assessment of their adverse risk to the organisms living in both ecosystems. New methods for the identification of these small particles are also distinguished; however, these techniques are not adequate and sufficient for detection, toxicity, and impacts of their effects on biota. The evidence of large burden of microplastics in aquatic ecosystems has substantially increased. But we are at the beginning of understanding of the potential risk of these materials in soil, where it is still entirely unclear what the size of this problem is. Up to now, little information is present about the effects of these particles on soil organisms. Better understanding to the occurrence, spread, and negative influence of these particles in the ecosystems is needed.

Recently, the rapid development of digital finance in China has exerted a subtle influence on many aspects of social and economic development. However, the research on the impact of digital finance on corporate green innovation is rather lacking. In order to fill this gap, this paper uses the “Peking University Digital Finance Index” to evaluate the micro impact of financial innovation development on environmental governance from the firm level. The results show that digital finance can significantly improve the quantity and quality of corporate green innovation, and this effect still exists after considering endogeneity and a series of robustness tests. The promotion effect of digital finance on the quantity and quality of corporate green innovation is more obvious in state-owned, eastern, and mature enterprises. In addition, we find the mechanism behind the positive relationship between digital finance and corporate green innovation: digital finance makes firms more transparent and funds flow more convenient. Overall, this paper provides a micro explanation of environmental governance for the accelerated popularization of digital finance in emerging markets, which is urgently needed for most emerging economies seeking high-quality development.

Raw and modified fibrous clay minerals palygorskite (Pal) and sepiolite (Sep) were tested for their ability to remove ammonium from ammonium polluted water. Palygorskite and sepiolite underwent thermal treatment at 400°C (T-Pal and T-Sep respectively). Raw and thermally treated samples were characterized using XRD, SEM, BET, FTIR, TGA, zeta potential, and XRF. The techniques verified the effect of thermal treatment on sample structures and the enhancement of negative charge. Both raw and thermally activated materials were applied in batch kinetic experiments, and found to be efficient adsorbents in their raw forms, since Pal and Sep achieved 60 and 80% NH₄⁺–N removal respectively within 20 min of contact for initial NH₄⁺–N concentration of 4 mg/L. Similar removal rates were gained for other concentrations representative of contaminated aquifers that were examined, ranging from 1 to 8 mg/L. Results for the modified T-Pal and T-Sep minerals showed up to 20% higher removal rate. Saturation tests indicated the positive effect of thermal treatment on the minerals since T-Pal and T-Sep removal efficiency reached 85% and remained stable for 24 h. However, competitive ions in real water samples can influence the NH₄⁺–N removal efficiency of the examined samples. At almost all the examined samples, the nonlinear Freundlich isotherm and linear pseudo-second kinetic models showed better fitted all examined samples thus indicating heterogeneous chemisorption.

The coronavirus disease (COVID-19) is a highly transmitted disease that spreads all over the globe in a short period. Environmental pollutants are considered one of the carriers to spread the COVID-19 pandemic through health damages. Carbon emissions, PM2.5 emissions, nitrous oxide emissions, GHG, and other GHG emissions are mainly judged separately in the earlier studies in different economic settings. The study hypothesizes that environmental pollutants adversely affect healthcare outcomes, likely to infected people by contagious diseases, including coronavirus cases. The subject matter is vital to analyze the preventive healthcare theory by using different environmental pollutants on the COVID-19 factors: total infected cases, total death cases, and case fatality ratio, in a large cross-section of 119 countries. The study employed the generalized least square (GLS) method for robust inferences. The results show that GHG and CO2 emissions are critical factors likely to increase total coronavirus cases and death rates. On the other hand, nitrous oxide, carbon, and transport emissions increase the case fatality ratio through healthcare damages. The study concludes that stringent environmental policies and improving healthcare infrastructure can control coronavirus cases across countries.

The placement of boulder or boulder cluster in rivers can increase or repair the complexity of river structure and the diversity of hydraulic conditions, which is very important for the habitat of many aquatic organisms. In this study, the diamond-type boulder cluster was modeled as four hemispheres exposed to a fully developed turbulent open channel flow. Numerical simulation was conducted to investigate the time-averaged flow characteristics, three-dimensional coherent structures, turbulence characteristics, and flow diversity index at different spacing ratios L/D (the ratio of the distance L to the diameter D, 1.0 ≤ L/D ≤ 3.5, where L is the center-to-center distance between two adjacent hemispheres and D is the diameter of the hemisphere). The results show that with the increase of the spacing ratio, the shear layer on the side of the gap flow gradually strengthens, and the single Karman vortex street in the wake region of the hemisphere array is suppressed. The time-averaged peak velocity in the gap flow gradually decreases with the increase of the spacing ratio, and the single of the recirculation zone behind the hemisphere array transforms into the recirculation zone behind each hemisphere, and the length of the each recirculation zone increases to the same. The turbulence intensity of the array first increases with the increase of the spacing ratio and then gradually decreases to a constant, reaching the peak intensity at L/D = 2. Based on the Shannon entropy concept, the flow diversity index in the zone of influence (ZOI) is calculated by considering the velocity and turbulence kinetic energy. The flow diversity index is the largest in the ZOI at the spacing ratio of 1.5.

Replacement of conventional feedstuffs with inexpensive and non-conventional ingredients such as quinoa may improve animal performance and the quality of their products. Quinoa supplementation is believed to have a good nutritive value as a ruminant feed, but evidence is scarce. The present experiment aimed to evaluate the nutritive value of whole, dried quinoa plant (Chenopodium quinoa) as a feed for ruminants. In the first experiment, the in sacco technique was used to evaluate nutrient disappearance and fermentation kinetics of quinoa. In the second experiment, the in vitro gas production technique was used to evaluate diets with substitution of clover hay with quinoa at 0 (Q0), 15 (Q15), 30 (Q30), and 45% (Q45) of the diets. Proximate analysis showed that quinoa contained about 18.6% crude protein (CP) with oleic acid, arachic acid, linoleic acid, and palmitic acid as the major fatty acids. The in sacco degradability showed that the “a” fraction of dry matter (DM) was low, while the fraction “b” was high for DM and CP. Replacing clover hay with quinoa did not affect gas or methane production; however, Q30 treatment quadratically increased (P < 0.05) its production. It is concluded that quinoa can be used as a feed for ruminants and can replace clover hay up to 45% in the diet.

In this work, buckwheat husks (Fagopyrum esculentum) were modified by acid treatment and posteriorly employed to remove the ketoprofen in batch adsorption. The characterization results indicated that a more irregular surface with new empty spaces was generated after acid treatment. The adsorptive process was favored at acidic pH = 3. The dosage of 0.85 g L⁻¹ was fixed for the kinetic and isothermal tests, obtaining good removal and capacity indications. The kinetic studies were better represented by pseudo-second-order, obtaining an experimental capacity of 74.3 mg g⁻¹ for 200 mg L⁻¹ of ketoprofen. An increase in temperature negatively affected the adsorption isotherm curves, resulting in a maximum capacity of 194.1 mg g⁻¹. Thermodynamic results confirmed the exothermic nature of the process with physical forces acting. The adsorbent presented high efficiency in treating a synthetic effluent containing different drugs and salts, 71.2%. Therefore, adsorbent development from buckwheat husks treated with a strong acid is an excellent alternative, given the good removal results and the low cost for its preparation.

The analysis and probabilistic health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in cereal products were done by using magnetic solid-phase extraction (MSPE) method and gas chromatography/mass spectrometric (GC/MS). The results of method showed LOQ and LOD of PAHs compounds were 0.105–0.180 and 0.035–0.060 µg/kg, and the recorded values were 4.3–12.1 and 6.1–20.3% for repeatability and reproducibility with an estimated recovery of 94.4–103.4%. In this study, we analyzed kind of bread (Barbari, Sangak, Baguette, Taftoon, Lavash), macaroni, lasagna, and cooked rice that mean of total PAHs were 98.2, 121.7, 134.9, 166.3, 176.3, 176.2, 130.1, and 248.3 μg/kg, respectively. Further, the correlation between the type and amount of 16 PAHs with cereal products samples evaluated with multivariate principal component analysis and heat map visualization. The highest incremental lifetime cancer risk (ILCR) was found in cooked rice (7.80E-6), while the lowest ILCR was found in Lasagna (2.35E-07). In conclusion, the PAHs content in the tested products were in low health risk ranges (1 × 10⁻⁶ < ILCR < 1 × 10⁻⁴), and all of the cereal products sold in Tehran are considered safe for consumers. Therefore, cereal products should be regularly evaluated and monitored by regulatory agencies to reduce contaminants in these high-consumption products.