PM₂.₅ induces pulmonary inflammation via oxidative stress, and this role in the lungs is widely accepted, but studies on whether oxidative stress and inflammation can self-recover and be fully restored are limited. In this study, the oxidative stress and inflammation in the lungs of rats, which were first exposed to different PM₂.₅ dosages (0, 0.5, 3.0, and 15.0 mg/kg body weight) and different recovery days (0, 15, and 30 days) and then were exposed to the same PM₂.₅ dosages (30 mg/kg b.w.) after 30 days of recovery, were investigated. Results showed that the activity of superoxide dismutase (SOD) was significantly inhibited, and the levels of malondialdehyde (MDA), inducible nitric oxide synthase (iNOS), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) significantly increased. These changes were accompanied with damage to the pathological structure of the rat lungs. After stopping PM₂.₅ exposure, the difference between the PM₂.₅ group and the control group gradually decreased with the extension of recovery time. However, when the rats were again exposed to the same dose of PM₂.₅, the levels of IL-6, IL-1β, TNF-α, MDA, and iNOS were significantly increased, and the activities of SOD and GSH-Px were significantly inhibited in the high-dose group. And the high-dose group was accompanied by more severe lung pathological structural damage. Results showed that PM₂.₅ could induce oxidative stress and inflammatory damage in the lungs of rats, and these damages gradually recovered as exposure ceased, but increased lung susceptibility in rats.

Until now, rare earth elements (REEs) recycled from the green phosphor of waste fluorescent lamps (FLs), essentially terbium, remain a major challenge. The sulfuric acid effect on leaching efficiency of REEs from phosphor powder (PP) is investigated in this paper. According to a composite central design, experimental leaching study is performed under various parameters (acid concentration, leaching temperature, and time as well as liquid-to-solid ratio (L/S)). A statistical model of experiments and an analysis of variance are studied in order to predict leaching process. The results showed that by decreasing concentration and L/S ratio while increasing leaching time at optimal temperature value permits profitable terbium extraction. Afterwards, the developed statistical model is explored for an optimized response surface methodology. The obtained results were tested experimentally and showed best terbium extraction with 75%. Moreover, 0.01% for the major contaminant, that is calcium, is reached. This low calcium yield may have a further advantage during REE recovery in the downstream. Therefore, resulting solution under optimal conditions is treated with oxalic acid followed by a calcination of the solid precipitate. Finally, 43.57% and 49.38% are produced for terbium and yttrium oxides, respectively.

The Estância Velha stream integrates the Sinos River Basin that provides drinking water in one of the most important Brazilian centers, the “Capital of tanneries,” and it receives effluents from tannery industries. In Brazil, water quality is monitored only through physicochemical and microbiological parameters, and considering the biomarkers’ importance in complementing the analysis, the present study was aimed at evaluating the environmental quality of the Estância Velha stream also through cytogenotoxic criteria, at the stream source (site 1), as well as upstream (site 2) and downstream (site 3) of the demographically most dense area. The results for dissolved oxygen, color, total phosphorus, silver, and thermotolerant coliforms classified the Estância Velha stream as class 4 in general; that is, the water is suitable only for navigation and to landscape harmony. Overall, the water was classified as poor by Water Quality Index (WQI) and as hypereutrophic by Trophic State Index (TSI). The main genotoxic alterations (micronuclei and nuclear buds) were observed in site 2, in which were obtained the highest levels of aluminum, silver, iron, and manganese. Despite this, most of the effluents released from the region are not treated prior to being discharged into the stream, suggesting the requirement for effluent treatment to ensure the quality of the water source available.

Quaternary ammonium salt type cotton linter (QCL) was synthesized by radiation grafting of dimethylaminoethyl methacrylate (DMAEMA) onto cotton linter and subsequent quaternization. Batch and column adsorption experiments were used to evaluate the adsorption behaviors of the QCL for phosphate. The adsorption kinetics of QCL for phosphate were well obeyed pseudo-second-order mode. The adsorption isotherms were well fitted by Langmuir, Temkin, and Dubinin–Radushkevich model. Column experiments showed that the breakthrough curves were dependent on the inlet concentration and flow rate but independent on space velocity. Moreover the QCL can be effectively regenerated for further repeated use at least 10 cycles. And QCL exhibited good selective adsorption for phosphate. Such high adsorption and desorption efficiency of QCL made it employing for phosphate adsorption in practical application.

Substantial discharge of hazardous substances, especially dyes and heavy metal ions to the environment, has become a global concern due to many industries neglecting the environmental protocols in waste management. A massive discharge of contaminantsfrom different anthropogenic activities, can pose alarming threats to living species and adverse effect to the ecosystem stability. In the process of treating the polluted water, various methods and materials are used. Hybrid nanocomposites have attained numerous interest due to the combination of remarkable features of the organic and inorganic elements in a single material. In this regards, carbon and polymer based nanocomposites have gained particular interest because of their tremendous magnetic properties and stability. These nanocomposites can be fabricated using several approaches that include filling, template, hydrothermal, pulsed-laser irradiation, electro-spinning, detonation induced reaction, pyrolysis, ball milling, melt-blending, and many more. Moreover, carbon-based and polymer-based magnetic nanocomposites have been utilized for an extensive number of applications such as removal of heavy metal and dye adsorbents, magnetic resonance imaging, and drug delivery. This review emphasized mainly on the production of magnetic carbon and polymer nanocomposites employing various approaches and their applications in water and wastewater treatment. Furthermore, the future opportunities and challenges in applying magnetic nanocomposites for heavy metal ion and dye removal from water and wastewater treatment plant.

In this study, action of ultrafiltered xylano-pectinolytic enzymes from a bacterial strain has been evaluated for bleaching of rice straw soda-anthraquinone pulp. Maximum bio-bleaching effect and release of non-cellulosic impurities were noticed with xylano:pectinolytic enzymes dose of 6.0:2.1-IU/g pulp, treatment time of 180 min at 10% pulp consistency, pH 8.5, and temperature 55 °C. Microscopic images of bio-bleached rice straw pulp also confirmed the efficacy of ultrafiltered enzymes, as bleaching agent. This bio-bleaching treatment resulted in 15.38% and 32% reduction in kappa number and active chlorine dioxide dose, respectively, along with increase in various physical properties, burst index (12.50%), tear index (19.07%), breaking length (14.30%), double fold number (26.31%), Gurley porosity (45.32%) and viscosity (16.17%). This bio-bleaching approach not only improved the pulp quality but also reduced environmental pollution load by decreasing effluent parameters values of BOD and COD by 23.67% and 27.44%, respectively. This study indicates that use of ultrafiltered xylano-pectinolytic synergism for rice straw pulp bleaching will ultimately help in making the process eco-friendly, along with better quality pulp. This is the first report on use of ultrafiltered xylanase and pectinase, produced from a bacterial isolate, for bleaching of rice straw pulp.

In Lake Erhai, water quality was affected by the basin nutrient discharge and climate change. To analyze the relationships between the water quality (total nitrogen [TN], total phosphorus [TP], chemical oxygen demand [CODmn], ammonia [NH₄], and trophic level index [TLI]) and basin nutrient discharge (TNd, TPd, and CODd) combined with climate changes (air temperature [AT], precipitation [pre], wind speed [wind], and sunshine hours [SHs]), the generalized additive model (GAM) was employed to explore the nonlinear relationships with their interactions using data sets ranging from 1999 to 2012. Our findings revealed that the water quality in Lake Erhai deteriorated in the early twentieth century, and the basin discharge and AT appeared significant (p < 0.05) rising trends in a long time, while the precipitation decreased significantly (p < 0.05) in the study period. Single-factor GAM results indicated that the basin nutrient discharge was the main explanatory factor for the variations of TN and TP in lake, while precipitation was the main driver for CODmn and NH₄. Besides, the water quality displayed nonlinear responses to the basin discharge, but all of the water quality variables went up as the emission levels increased in the lower range. The results showed that the water quality deteriorated in the lower rainfall, and TN rose as the AT increases, while TP was elevated accompanied by the ascending SHs there. The GAM interaction results suggested that the increase of AT and TPd had a promoting effect on TP in Lake Erhai. Stricter nutrient management measures should be implemented when the impacts of climate change are taken into account.

Integrated constructed wetland into activated sludge process has a potential in improving treated wastewater with high organic loading. However, biological activities on those processes will generate microbial by-products from substrate metabolism and cell lysis. The presence of those compounds in effluent of wastewater treatment causes problems in source water. This study combines fluorescence excitation emission matrices (FEEM) with high-performance size exclusion chromatography with fluorescence detector (HPSEC-FLD) to characterize molecular weight–based fluorescent of organic matter and its removal in combination of constructed wetland with activated sludge process. The results show that three components of fluorescence organic: fulvic acid–like (Ex/Em 250/440 nm), SMP-like (Ex/Em 280/350 nm), humic acid–like (Ex/Em 340/420 nm), have been identified in all samples by the FEEM. Further, the HPSEC-FLD, which was set up based on chosen fluorescence wavelength, revealed two different apparent molecular weight (AMW) fractions: high molecular weight (HMW)/biopolymer (50,000 Da) and medium molecular weight (MMW)/humic substance–like (3000–650 Da). Peak-fitting determines that the area of MMW is higher than the area of HMW of all fluorescence organic components, and the area of HMW of fluorescence fulvic acid–like is comparable with the area of SMP-like, and no HMW of humic acid–like detected. Humic acid–like and fulvic acid–like were removed during treatment, while metabolite by-product were released as shown by increasing fluorescence SMP-like and TOC concentration. This method gives new insight to characterize organic matter for assessing effluent of wastewater quality and determining the appropriate water treatment.

Heavy metal pollution in river sediments is one of the most serious problems in the aquatic environment. In this study, thirty-two surface sediment and overlying water samples were collected to evaluate the nutrient levels and heavy metal contents (Mo, Cu, Zn, Ni, Cd, Pb, and Cr) in the Hai River and its tributaries, which is the largest river flowing into Bohai Bay. The enrichment degree and geoaccumulation value of the studied metals decreased in the same order of Cd > Cu > Pb > Mo > Ni > Zn > Cr, and the mean contents of Cu and Cd were 2.58 and 2.93 times as high as their background values in Tianjin. Cd contributed over 50% of the ecological risk at the thirty-two sites. Moreover, according to the results of multivariate statistical analyses, Cu and Cd were mainly derived from anthropogenic sources, the quality of overlying water except COD influenced the distribution of heavy metals, and Cd had no correlations with the other heavy metals.

Composting has various benefits to achieve sustainability, such as substituting the use of fertilizers and preventing organic residues from being dumped in landfills. Thus, the objective was to evaluate nutrient and heavy metal release dynamics during composting with different mixtures of organic residues containing food wastes. The study was conducted in a community association in Mossoró, Rio Grande do Norte, Brazil, and the chemical analysis was carried out at the Universidade Federal Rural do Semi-Árido. Proportions between bovine manure (BM) and food wastes (FW) were Pile 1–0:3 (0% BM and 30% FW); Pile 2–1:2 (10% BM and 20% FW); Pile 3–1:1 (15% BM and 15% FW); Pile 4–2:1 (20% BM and 10% FW); Pile 5–3:0 (30% BM and 0% FW) (Pile considered as control), and the remaining 70% was filled with plant residues (tree prunings). Increment of BM proportion in compost piles with FW led to increase in C mineralization, but C mineralization decreased in the pile with only tree prunings and BM. Nitrogen immobilization occurred only in the pile with 15% BM and 15% FW; in the others, N was mineralized. Food wastes showed greater amounts of potentially mineralizable K fractions. For the micronutrients copper and zinc, in general, the initial contents decreased, whereas iron contents increased. The contents of all heavy metals diminished in the final product of the composting process, with no risk of contamination.