The purpose of this study was to investigate the possibility of using zinc oxide nanoparticles (ZnONPs) instead of silver nanoparticles (AgNPs) for removing Aeromonas hydrophila from water used to culture Cyprinus carpio juvenile. Antibacterial materials as filter media were prepared by coating ZnONPs (two coating methods, referred as ZnA and ZnB) or AgNPs (referred as Ag) on the porous surfaces of zeolite beads. The characterization of coated samples was determined using FESEM, EDS, and GFAAS. The antibacterial activities of prepared samples were evaluated by the zone of inhibition test, tube test, and flow test. The diameter of inhibitory zones formed by ZnONP- and AgNP-coated zeolite beads was significantly higher than uncoated zeolite (control) (P < 0.05). Also, the tube test results revealed 100% killing of the bacterial cells after 24 h of contact to all coated materials. In the flow test (without fish), the antibacterial efficiency of filter columns that contained ZnA, ZnB, and Ag found to be 34.84, 23.77, and 100% after 96 h, respectively. The mortality rate of carp juveniles cultured in infected water treated with AgNP filters was significantly lower than those cultured in infected water or treated with ZnONPs filters (P < 0.05). The results indicated that although ZnONP filter media have somewhat antimicrobial properties (especially in vitro), their ability to complete removal of microorganisms from the water is not as high as AgNP filters. So, it still seems that zeolite coated with AgNPs has a higher potential for water disinfection in aquaculture.

The performance of both adsorption and heterogeneous photo-Fenton processes, combined for the first time for the treatment of a real winery wastewater (WW), was evaluated under different operational conditions. A Portuguese natural Ca-smectite (Ca-Sm) was applied in both processes, however, with different purposes: (1) as an adsorbent, which reveals great capacity to retain organic acids, and (2) as catalyst support for the production of an iron-based catalyst (Fe-Sm). Both Ca-Sm and Fe-Sm materials were characterized by XRD, FTIR, low temperature N₂ adsorption isotherms, and SEM-EDX. The adsorption process was investigated under different experimental conditions, namely, different pH, adsorbent dosages, and different concentrations of the organic contaminant. The adsorption isotherm was successfully described by Jovanovich isothermal model (R² = 0.990), which predicted a maximum adsorption capacity of 161 mg C/g. Regarding to the heterogeneous photo-Fenton process, the higher TOC removal percentage obtained (78.7% - 240 min) was achieved at pH 4.0, with a H₂O₂ concentration of 98 mM and a catalyst dosage (S:L, solid:liquid ratio) corresponding to 6.00 g/L (UV-C). As a result, the combination of both treatment processes, using the optimized conditions, allowed a total TOC removal of 90%, where the initial TOC₀ (825 mg C/L) was reduced by 54%, through the adsorption process, and by 36% by means of heterogeneous photo-Fenton process [TOC₀ = 825 mg C/L (1) – TOCf₋ₐdₛ = 380 mg C/L (2) – TOCf₋ₚF = 81 mg C/L (3)].

With the widespread use of metal oxide nanoparticles (MNPs), agricultural soil is gradually becoming a primary sink for MNPs. The effect of these nanoparticles on the fate and the toxicity of co-existing heavy metals is largely unknown. In this paper, pot experiments were conducted to evaluate the impact of ZnO nanoparticles (ZnO-NPs) on Cd toxicity and bioaccumulation in a soil-rice system. Different amounts of ZnO-NPs were added to three different levels of Cd-contaminated paddy soil (L-Cd, 1.0 mg kg⁻¹; M-Cd, 2.5 mg kg⁻¹; H-Cd, 5.0 mg kg⁻¹). The results showed that the addition of ZnO-NPs significantly increased the soil pH value, and the soil pH value increased with the increase in ZnO-NP concentration. Reductions in plant height and biomass under Cd stress were recovered and increased after the addition of ZnO-NPs; the addition of ZnO-NP promoted rice biomass increased by 13~22% and 25~43% in the M-Cd and H-Cd groups, respectively, compared with that of the respective control treatment. A high concentration of ZnO-NPs could increase the concentration of bioavailable Cd in rhizosphere soil. In the L-Cd group, the Cd concentration of the rice in the L-Z500 treatment increased to 0.51 mg kg⁻¹, exceeding the limit for acceptable Cd concentrations in rice of China (0.2 mg kg⁻¹). This work revealed that ZnO-NPs could improve plant growth, especially in the early-growth stage, and alleviate the toxic effects of Cd. However, the addition of high-concentration (500 mg kg⁻¹) ZnO-NPs in the lower Cd pollution soil could significantly facilitate the accumulation of Cd by Oryza sativa L.

A distinctive process (BCE-MFC) was developed to explore the methyl orange (MO) degradation and simultaneous bioelectricity generation based on the functional collaboration of biofilm, electrolysis, constructed wetland, and microbial fuel cell. The biofilm-cathode electrode–microbial fuel cell (BCE-MFC) was capable of sustaining an excellent MO removal (100%) and bioelectricity production (0.63 V). BCE significantly enhanced MO biodegradability, thus resulting in a 56.3% improvement of COD removal in subsequent MFC. Bacillus was dominant in biofilm on cathode in BCE. In MFC, Proteobacteria phylum (64.84%) and Exiguobacterium genus (13.30%) were predominated in the anode region, probably basically responsible for electricity generation. Interestingly, relatively high content of Heliothrix sp. (9.94%) was found in the MFC designed here, which was likely to participate in electricity production as well. The proposed functional collaboration may be an effective strategy in refractory wastewater treatment and power production.

In freshwater ecosystem, phototrophic biofilms play a crucial role through adsorption and sequestration of organic and inorganic pollutants. However, extracellular polymeric substance (EPS) secretion by phototrophic biofilms exposed to metals is poorly documented. This work evaluated the physiological responses of phototrophic biofilms by exposing three microorganisms (cyanobacterium Phormidium autumnale, diatom Nitzschia palea and green alga Uronema confervicolum) to 20 and 200 μg L⁻¹ of Cu or 60 and 600 μg L⁻¹ of Zn, both individually and in combination. Analysis of metal effects on algal biomass and photosynthetic efficiency showed that metals were toxic at higher concentrations for these two parameters together and that all the strains were more sensitive to Cu than to Zn. U. confervicolum was the most impacted in terms of growth, while P. autumnale was the most impacted in terms of photosynthetic efficiency. In consequence to metal exposure at higher concentrations (Cu200, Zn600 and Cu200Zn600), a higher EPS production was measured in diatom and cyanobacterium biofilms, essentially caused by an overproduction of protein-like polymers. On the other hand, the amount of secreted polysaccharides decreased during metal exposure of the diatom and green alga biofilms. Size exclusion chromatography revealed specific EPS molecular fingerprints in P. autumnale and N. palea biofilms that have secreted different protein-like polymers during their development in the presence of Zn600. These proteins were not detected in the presence of Cu200 despite an increase of proteins in the EPS extracts compared to the control. These results highlight interesting divergent responses between the three mono-species biofilms and suggest that increasing protein production in EPS biofilms may be a fingerprint of natural biofilm against metal pollutants in freshwater rivers.

Erhai is a famous tectonic rift lake in China. In this study, the distribution of nitrogen and phosphorus species in Erhai sediment cores and their ecology risk were evaluated. The total nitrogen (TN) in the sediment cores ranged from 1583.3 to 8018.5 mg/kg. Nitrogen (N) was still accumulating in the sediment. For depths of 0 to 25 cm, the TN decreased dramatically and for deeper depths the TN got stabilized. The proportions of various N fractions in the sediments of the study areas ranked as follows: the strong oxidation extractable N (SOEF-N) > the weak acid extractable N (WAEF-N) > the strong alkali extractable N (SAEF-N) > the ion-exchangeable N (IEF-N). The total phosphorus (TP) ranged from 814.9 to 1442.3 mg/kg. The vertical distribution of each fraction of phosphorus showed that there were different sources of sediment phosphorus around the Erhai Lake. The results of nitrogen and phosphorus pollution evaluation in sediments by single pollution standard index method showed that the standard index of the TN (STN) ranged from 4.29 to 14.01, and the standard index of the TP (STP) ranged from 1.69 to 2.18. It illustrated that N and P in the sediments were the serious ecological pollution risks in Erhai Lake.

The dissemination of extended spectrum beta-lactamases (ESBL) genes through gene transfer attracts wide attention. Bentonite is widely used as a feed additive in an animal-breeding environment. In order to obtain a better understanding of the effect of bentonite on Escherichia coli carrying ESBL gene, proteomic analysis was carried out to screen the key proteins. The results showed that a total of 31 proteins were differentially expressed, including 21 up-regulated proteins and 10 down-regulated proteins. These proteins were involved in biosynthetic process, metabolic process, stress response, transport, anaerobic respiration, proteolysis, hydrolase, protein folding, transcription, salvage, and other. The transcriptional level of four genes (mipA, gntY, tldD, and arcA) was in consensus with proteomic results. This study revealed the differentially expressed proteins involved when E. coli was incubated under bentonite and PBS condition, which implied the possibility that bentonite may promote the transfer of ESBL gene between E. coli.

Non-edible seeds are not used in any commercial applications, which implies that they can be used for biofuel applications. The present study aimed to maximise the process conditions for oil extraction and sterculia biodiesel production from Sterculia foetida (poon oil). GC-MS identified the methyl esters of sterculia oil as sterculic acid (32%), palmitic acid (15.88%), oleic acid (10.00%), linoleic acid (9.95%) and malvalic acid (9%). Response surface methodology (RSM) based parametric optimisation of oil extraction was carried out by choosing process variables such as sample weight, volume of solvent to seed ratio and time. The optimum sample amount of 7.5 g and the volume of solvent to seed ratio of 40 mL/g resulted in a maximum oil yield of 45.27% at 3 h. The results were statistically significant (P < 0.05) with a regression coefficient (R²) of 0.9988. Furthermore, the artificial neural network (ANN) resulted in an R² value greater than 0.9, which validates the RSM. Conventional optimisation of the temperature (55 °C), feedstock to methanol ratio (1:12), catalyst proportion (1.5%) and transesterification reaction time (60 min) yield 90.87% biodiesel production. The physicochemical characteristics of oil and biodiesel complied with the requirements of the ASTM standards. The rate constant and thermodynamic variables at the optimum temperature (333 K) were calculated from the experimental data. The activation energy (Eₐ), activation enthalpy in transition state theory (ΔH⁺⁺), activation entropy in transition state theory (ΔS⁺⁺) and Gibbs free energy in transition state theory (ΔG⁺⁺) were 37.91 kJ mol⁻¹, 35.14 kJ mol⁻¹, − 239.58 J mol⁻¹ K⁻¹ and 79.81 kJ mol⁻¹ respectively. Graphical abstract

Researchers dealing with heat stress experiments use different cell kinds and use trypsin that has been reported to affect the cellular proteins of cultured cells. Therefore, we compared the effects of acute and chronic exposures to high temperature (45 °C) on camel skin fibroblast and granulosa cells. Primary culture of fibroblasts and granulosa cells tolerated the acute heat shock for 2 h; however, granulosa cells cultured for long duration (20 h) showed thermotolerance when compared with the fibroblasts. Moreover, the effect of cell dispersion method (trypsin and mechanical dissociation) on the thermotolerance of sub-cultured cells was examined. Trypsin altered the morphology of fibroblasts and granulosa cells exposed to 45 °C for 4 h. Moreover, trypsin significantly reduced the fibroblast and granulosa cell migration in the wound healing assay. The current results demonstrate that cell passaging and cell type can affect the thermotolerance of the cells; it also revealed that trypsin could alter the cellular response to the heat shock. We raise the demand for another alternative method for cell dispersion in experiments dealing with cellular responses to the heat shock.

This paper conducts a convergence analysis on the energy-environmental efficiency to explore the differences between regions that reflect the implementation effect of the policies on energy-saving and emission reduction. Particularly, for the Yangtze River urban agglomeration, additive model (AM model) is applied to calculate the energy-environmental efficiency, and the convergence model is employed to analyze the heterogeneity and spatial evolution of energy-environmental efficiency. From the results, the energy-environmental efficiency for Suzhou is at a good level; the figures for Wuxi, Yangzhou, and Nantong maintain at medium level; for Zhenjiang, qualified level; and for Nanjing, Changzhou, and Taizhou, poor level. The energy-environmental efficiency of the whole Yangtze River urban agglomeration displays a downward trend of fluctuations. While Nantong reveals a divergent energy-environmental efficiency, Zhenjiang, Changzhou, Wuxi, Yangzhou, and Nanjing Cities generally show a trend of convergence. It was also recognized that the energy-environmental efficiency is gradually decreasing from Southeast to North to Southwest regions. In the past decade, the north region of Yangtze River yielded a divergent development trend, while the southeast and southwest regions appear to have a convergent development trend. In the future, the urban agglomeration needs to promote the coordinated development of the economy and the energy environment, impel the optimization and upgrading of the industrial structure, narrow the regional gap, and adjust the energy consumption habits.