Metal-oxide nanoparticles (NPs), as a new emerging technological compound, promise a wide range of usage areas and consequently have the potential to cause environmental toxicology. In the present work, aluminum (Al₂O₃), copper (CuO), and titanium (TiO₂) nanoparticles (NPs) were administered via oral gavage to mature female rats (Rattus norvegicus var. albinos) for 14 days with a dose series of 0 (control), 0.5, 5, and 50 (mg/kg b.w./day). Enzyme activities of the antioxidant system such as catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S-transferase (GST), and glutathione reductase (GR) in the liver were measured. Transmission electron microscope (TEM) images of the liver were taken to demonstrate NP accumulation and distribution in liver tissue. Data showed that all NPs caused some significant (P > 0.05) alterations in the activities of antioxidant enzymes. CAT activity increased after CuO and TiO₂ administrations, while SOD activity decreased after Al₂O₃ administration. The activities of enzymes associated with glutathione (GR, GPx, GST) metabolisms were also significantly altered by NPs. GPx activity increased in rats received Al₂O₃, CuO NPs, while GR activity increased only by Al₂O₃. However, there were increases (TiO₂) and decreases (CuO) in GST activity in the liver of rats. TEM images of the liver demonstrated that all NPs accumulated in the liver, even at the lowest dose. This study indicated that the antioxidant enzymes in the liver of rats were affected by all NPs, suggesting the antioxidant system of rats suffered after NP administration.

This study investigates the removal of selected pharmaceuticals, as recalcitrant organic compounds, from synthetic wastewater using an electro-membrane bioreactor (eMBR). Diclofenac (DCF), carbamazepine (CBZ), and amoxicillin (AMX) were selected as representative drugs from three different therapeutic groups such as anti-inflammatory, anti-epileptic, and antibiotic, respectively. An environmentally relevant concentration (10 μg/L) of each compound was spiked into the synthetic wastewater, and then, the impact of appending electric field on the control of membrane fouling and the removal of conventional contaminants and pharmaceutical micropollutants were assessed. A conventional membrane bioreactor (MBR) was operated as a control test. A reduction of membrane fouling was observed in the eMBR with a 44% decrease of the fouling rate and a reduction of membrane fouling precursors. Humic substances (UV₂₅₄), ammonia nitrogen (NH₄-N), and orthophosphate (PO₄-P) showed in eMBR removal efficiencies up to 90.68 ± 4.37, 72.10 ± 13.06, and 100%, respectively, higher than those observed in the MBR. A reduction of DCF, CBZ, and AMX equal to 75.25 ± 8.79, 73.84 ± 9.24, and 72.12 ± 10.11%, respectively, was found in the eMBR due to the enhanced effects brought by electrochemical processes, such as electrocoagulation, electrophoresis, and electrooxidation.

Varying concentrations of soil Cr(VI) were used in order to explore the tolerance thresholds and phytoremediation potential of Greek oregano (Origanum vulgare), in a pot experiment conducted outdoors. Oregano exhibited a rather exceptional capacity to bioaccumulate Cr in both the aerial part (up to 1200 mg of total Cr kg⁻¹ DM) and the root—reaching 4300 mg kg⁻¹ DM when grown in soil [Cr(VI)] of 150–200 mg kg⁻¹. Plant responses indicated that there was a threshold set at 100 mg Cr(VI) kg⁻¹ in the soil, above which the following results were recorded: (i) a restriction of Cr translocation from below- to above-ground plant part, (ii) a raise of the soil-to-root Cr transfer, and (iii) the Cr(III) evolution from the reduction of Cr(VI) was significantly decelerated in the root and accelerated in the aerial part. Soil [Cr] that surpassed this threshold challenged plant tolerance, resulting in a dose-dependent reduction of growth and antioxidant phenolics pool. Nonetheless, the significant Cr uptake capacity at plant level accounted for the considerably short remediation time (i.e., 29 years at soil [Cr(VI)] of 150 mg kg⁻¹) calculated according to these results. The overall performance of oregano indicated that phytoremediation would be feasible at sites with Cr contamination levels ranging within the above-defined thresholds.

The low-cost composite film was prepared by incorporating chitosan, berry soap fruit extract (rarasaponin), and bentonite as the raw materials. The produced chitosan/rarasaponin/bentonite (CRB) composite exhibits outstanding adsorption capability toward copper metal ions (Cu(II)). A series of static adsorption experiments were carried out to determine the isotherm and kinetic properties of CRB composite in the adsorption process. The adsorption equilibrium shows a good fit with the Langmuir isotherm model; the CRB composite has maximum uptake of Cu (II) of 412.70 mg/g; the kinetic adsorption data exhibit a good fit with the pseudo-second-order model. The thermodynamic parameters, ΔH°, ΔG°, and ΔS°, obtained from the isotherm data indicate that the uptake of copper ions by CRB composite is more favored at low temperatures. This study shows that physicochemical modified adsorbent, namely CRB composite, can remove Cu (II) better than pristine adsorbent of AAB and chitosan. The CRB composite also shows potential reusability.

The lignin-based carbon fibers were prepared by electrospinning followed by stabilization, carbonization, and activation (i.e., steam activation, one-step KOH activation, and metal activation). The effect of carbonization temperature on prepared carbon fibers (CFs) was investigated. As a result, 800 °C is the most suitable carbonization temperature because the prepared carbon fibers possess greater specific surface area and pore volume. With the help of various characterization methods, the structural characteristics of the activated carbon fibers (ACFs) prepared by the three activation methods and the adsorption performance of toluene were compared. It was observed that the activated carbon fibers prepared by KOH one-step activation method (ACFK) exhibited higher specific surface area (1147.16 m²/g) and greater toluene adsorption (463 mg/g). Particularly, abundant microporous structures and surface functional groups play a vital role in the adsorption process. Further, the adsorption performance of toluene onto ACFK was further investigated in a gas-phase dynamic adsorption system and the results showed that ACFK has great potential application in adsorption of volatile organic compounds.

Fluxes of methane (CH₄) and nitrous oxide (N₂O) from two rice varieties, Huayou 14 and Hanyou 8, were monitored using closed chamber/gas chromatography method. Huayou 14 is a commonly grown variety of rice whereas Hanyou 8 is a water-saving and drought-resistant rice (WDR) variety. Low soil volumetric water content (VWC) existed in the treatments on the slope (W5 < W4 < W3 < W2). On the slope, rice yields of Hanyou 8 decreased by 12–39%, and Huayou 14 by 11–46% as compared to the plots on the flat. The total compatible solutes in Hanyou 8 had a greater variational range than Huayou 14. Compared to W1, CH₄ emissions from W2–W5 decreased by 58–86% in Hanyou 8 and 38–86% in Huayou 14, whereas those of N₂O increased by 26–121% in Hanyou 8 and 49–189% in Huayou 14 across both two seasons, which was mainly because the VWC varied in W2–W5 treatment. Under the treatments in the slope (W2, W3, W4, and W5), the global warming potential (GWP) was dominated by N₂O emissions, which accounted for 69–90% of the GWP. Hanyou 8 had greater tolerance for water stress than Huayou 14 did, as evident from the smaller reductions in rice yield and greater variational range of total compatible solutes content. Water stress could reduce CH₄ emissions but decrease N₂O emissions for both rice varieties. This results suggest that planting WDR varieties under water shortage irrigation (such as W4, W5) will be able to maintain rice yields and reduce the GWP with less water.

The aim of this study was to develop a laboratory-scale anaerobic dynamic membrane bioreactor (AnDMBR) for the treatment of high-strength synthetic and real cheese whey wastewater. We determined the appropriate pore size for a convenient type of support material (nylon mesh) to optimize cake layer formation. The performance of the AnDMBRs was measured in terms of chemical oxygen demand (COD) and solids removal efficiencies. During high-strength synthetic wastewater treatment, the 70-μm pore size AnDMBR achieved COD removal efficiencies of 78% and 96% with COD loading rates of 4.03 and 2.34 kg m⁻³ day⁻¹, respectively, while the 10-μm pore size AnDMBR achieved 66% and 92% COD removal efficiencies at COD loading rates of 5.02 and 3.16 kg m⁻³ day⁻¹. The 10 μm pore size AnDMBR was operated in two periods: first period and second period (before and after physical cleaning) during high-strength synthetic wastewater treatment. The 10-μm pore size AnDMBR removed 83% and 88% of suspended solids during period 1 and period 2, respectively. Furthermore, using a pore size of 10 μm retained 72% of solids (973 mg L⁻¹) in the reactor outlet. The 10-μm pore size AnDMBR performed better than the 70-μm pore size AnDMBR in terms of cake layer formation. The 10-μm pore size AnDMBR was used to treat real cheese whey wastewater, resulting in COD removal efficiencies ranging from 59% (4.32 kg m⁻³ day⁻¹) to 97% (5.22 kg m⁻³ day⁻¹). In addition, 85% of suspended solids were removed from real cheese whey wastewater after treatment. The results show that dynamic membrane technology using a pore size of 10 μm can be used to treat real industrial wastewater.

Glucocorticoids in sewage treatment plant effluent discharged into rivers could influence microbial community structure in river-based aquifer media and affect groundwater quality. The effect of representative natural and synthetic glucocorticoids, namely, hydrocortisone (CRL) and dexamethasone (DEX), on the microbial communities in three types of river-based aquifer media was evaluated. The aquifer media was taken from the Beijing Chaobai River (BJ), Hebei Hutuo River (HB), and Tianjin Duliujian River (TJ) and they exhibited different physicochemical and biological properties. The attenuation rates of CRL were 0.175, 0.119, and 0.096 day⁻¹ and for DEX were 0.222, 0.151, and 0.113 day⁻¹ in the media from BJ, HB, and TJ, respectively. All the attenuation rates followed first-order kinetics. The biodiversity decreased significantly with CRL and DEX amendment. The microbial community composition differed in relation to the type of aquifer media and glucocorticoids, especially for BJ at the phylum level. In BJ, the major bacterial genus was Bacillus and in HB it was Rhodobacter. However, in TJ, three bacterial genera (Methylophilus, Methylobacillus, and Methylotenera) and Candidatus_Nitrososphaera were predominant in the microflora. All these genera were able to degrade both CRL and DEX. Distance-based redundancy analysis revealed that total organic carbon (TOC), the type of glucocorticoid, and the pH were the main factors explaining the variations in microbial community composition.

The objectives of this study were to (1) conduct laboratory bench and column experiments to determine the oxidation kinetics and optimal operational parameters for trichloroethene (TCE)-contaminated groundwater remediation using potassium permanganate (KMnO₄) as oxidant and (2) to conduct a pilot-scale study to assess the efficiency of TCE remediation by KMnO₄ oxidation. The controlling factors in laboratory studies included soil oxidant demand (SOD), molar ratios of KMnO₄ to TCE, KMnO₄ decay rate, and molar ratios of Na₂HPO₄ to KMnO₄ for manganese dioxide (MnO₂) production control. Results show that a significant amount of KMnO₄ was depleted when it was added in a soil/water system due to the existence of natural soil organic matters. The presence of natural organic material in soils can exert a significant oxidant demand thereby reducing the amount of KMnO₄ available for the destruction of TCE as well as the overall oxidation rate of TCE. Supplement of higher concentrations of KMnO₄ is required in the soil systems with high SOD values. Higher KMnO₄ application resulted in more significant H⁺ and subsequent pH drop. The addition of Na₂HPO₄ could minimize the amount of produced MnO₂ particles and prevent the clogging of soil pores, and TCE oxidation efficiency would not be affected by Na₂HPO₄. To obtain a complete TCE removal, the amount of KMnO₄ used to oxidize TCE needs to be higher than the theoretical molar ratio of KMnO₄ to TCE based on the stoichiometry equation. Relatively lower oxidation rates are obtained with lower initial TCE concentrations. The half-life of TCE decreased with increased KMnO₄ concentrations. Results from the pilot-scale study indicate that a significant KMnO₄ decay occurs after the injection due to the reaction of KMnO₄ with soil organic matters, and thus, the amount of KMnO₄, which could be transported from the injection point to the downgradient area, would be low. The effective influence zone of the KMnO₄ oxidation was limited to the KMnO₄ injection area (within a 3-m radius zone). Migration of KMnO₄ to farther downgradient area was limited due to the reaction of KMnO₄ to natural organic matters. To retain a higher TCE removal efficiency, continuous supplement of high concentrations of KMnO₄ is required. The findings would be useful in designing an in situ field-scale ISCO system for TCE-contaminated groundwater remediation using KMnO₄ as the oxidant.

It is the key point to reveal the effect of irrigation water and fertilization conditions on the agriculture non-point pollution in the paddy field. In this study, the estimation model of agricultural non-point source pollution loads at field scale was established on the basis of agricultural drainage irrigation model and combined with pollutant concentration predication model. Based on the estimation model of agricultural non-point source pollution in the field and experimental data, the load of agricultural non-point source pollution in different irrigate amount and fertilization schedule in paddy field was calculated. The results showed that the variation of field drainage varies greatly under different irrigation conditions, and there is an “inflection point” between the irrigation water amount and field drainage amount. The non-point pollution load increased with the increase of irrigation water and showed a significant power correlation. Under the different irrigation condition, the increase amplitude of non-point pollution load with the increase of irrigation water was different. When the irrigation water is smaller, the non-point pollution load increase relatively less, and when the irrigation water increased to inflection point, the non-point pollution load will increase considerably. In addition, there was a positive correlation between the fertilization and non-point pollution load. The non-point pollution load had obvious difference in different fertilization schedule even with same fertilization level, in which the fertilizer pollution load increased the most in the period of turning green to tillering. The results provide some basis for the field control and management of agricultural non-point source pollution.