Rational design of waste anode graphite-derived carbon catalyst to activate peroxymonosulfate for atrazine degradation.

As the rapidly growing number of waste lithium-ion batteries (LIBs), the recycling and reutilization of anode graphite is of increasing interest. Converting waste anode graphite into functional materials may be a sensible option. Herein, a series of carbonaceous catalysts (TG) were successfully prepared using spent anode graphite calcined at various temperatures and applied for activating peroxymonosulfate (PMS) to degrade atrazine (ATZ). The catalyst obtained at 800 °C (TG-800) showed the optimum performance for ATZ removal (99.2% in 6 min). Various experimental conditions were explored to achieve the optimum efficiency of the system. In the TG-800/PMS system, free radicals (e.g., SO4·-, HO·), singlet oxygen (1O2), together with a direct electron transfer pathway all participated in ATZ degradation, and the ketonic (CO) group was proved as the leading catalytic site for PMS activation. The potential degradation routes of ATZ have also been presented. According to the toxicity assessment experiments, the toxicity of the intermediate products decreased. The reusability and universal applicability of the TG-800 were also confirmed. This research not only provides an efficient PMS activator for pollutant degradation, but also offers a meaningful reference for the recovery of waste anode graphite to develop environmentally functional materials.

Assessment of metal pollution and effects of physicochemical factors on soil microbial communities around a landfill.

The physicochemical properties, chemical fractions of six metals (Cu, Zn, Pb, Cd, Cr, and Mn), and microbial communities of soil around a typical sanitary landfill were analyzed. The results indicate that soils around the landfill were from neutral to weak alkalinity. The contents of organic matter (OM), total nitrogen (TN), total phosphorous (TP), and activities of catalase, cellulase, and urease were significantly higher in landfill soils than those in background soils. Negative correlations were found between pH and metals. Cr was the dominant metal. Cu, Pb, Cr, and Mn were accumulated in the nearby farmland soils. Cd had the highest percentage of exchangeable fraction (33.7%-51.8%) in landfill and farmland soils, suggesting a high bioavailability to the soil environment affected by the landfill. Pb, Cr, and Mn existed mostly in oxidable fraction, and Cu and Zn were dominant in residual fraction. There was a low risk of soil metals around the landfill based on the RI values, while according to RAC classification, Cd had high to very high environmental risk. The MisSeq sequencing results showed that Actinobacteria, Proteobacteria, Chloroflexi, and Acidobacteria were the dominant phyla of bacteria, and the most abundant phylum of fungi was Ascomycota. The NMDS analysis revealed that the landfill could influence soil fungal communities more intensely than bacterial communities. TN, cellulase, and bioavailable metals (Pb-Bio and Cr-Bio) were identified to have main influences on microbial communities. Pb-Bio was the most dominant driving factor for bacterial community structures. For fungi, Pb-Bio was significantly negatively related to Olpidiomycota and Cr-Bio had a significantly negative correlation with Ascomycota. It manifests that bioavailable metals play important roles in assessing environmental risks and microbial community structures of soil around landfill.

Impact of soil physicochemical factors and heavy metals on co-occurrence pattern of bacterial in rural simple garbage dumping site.

Rural waste accumulation leads to heavy metal soil pollution, impacting microbial communities. However, knowledge gaps exist regarding the distribution and occurrence patterns of bacterial communities in multi-metal contaminated soil profiles. In this study, high-throughput 16 S rRNA gene sequencing technology was used to explore the response of soil bacterial communities to various heavy metal pollution in rural simple waste dumps in karst areas of Southwest China. The study selected three habitats in the center, edge, and uncontaminated areas of the waste dump to evaluate the main factors driving the change in bacterial community composition. Pollution indices reveal severe contamination across all elements, except for moderately polluted lead (Pb); contamination severity ranks as follows: Mn > Cd > Zn > Cr > Sb > V > Cu > As > Pb. Proteobacteria, Actinobacteria, Chloroflexi, and Acidobacteriota predominate, collectively constituting over 60% of the relative abundance. Analysis of Chao and Shannon indices demonstrated that the waste dump center boasted the greatest bacterial richness and diversity. Correlation data indicated a predominant synergistic interaction among the landfill's bacterial community, with a higher number of positive associations (76.4%) compared to negative ones (26.3%). Network complexity was minimal at the dump's edge. RDA analysis showed that Pb(explained:46%) and Mn(explained:21%) were the key factors causing the difference in bacterial community composition in the edge area of the waste dump, and AK(explained:42.1%) and Cd(explained:35.2%) were the key factors in the center of the waste dump. This study provides important information for understanding the distribution patterns, co-occurrence networks, and environmental response mechanisms of bacterial communities in landfill soils under heavy metal stress, which helps guide the formulation of rural waste treatment and soil remediation strategies.

Health risk assessment and potential sources of metals in riparian soils of the Wujiang River, China.

In order to understand the pollution status of metals in the riparian soils along the Wujiang River, 26 sampling sites in the mainstream and tributary streams were selected for investigation. The geo-accumulation index (Igeo), Nemerow integrated pollution index, and potential ecological risk index were applied to evaluate the contamination status and ecological risks of metals. Results revealed that the average concentrations of As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn were 12.20, 0.51, 84.01, 57.42, 922.57, 38.37, 38.06, and 127.82 mg/kg, respectively. The metal contamination degree and ecological risks in the upper reaches were significantly higher than those in the middle and lower reaches of the Wujiang River. Cd was the dominant contamination metal. Significant non-carcinogenic and carcinogenic risks of metals were found in children based on the hazard index and carcinogenic risk. As was the main non-carcinogenic and carcinogenic pollutant metal in both adults and children. According to principal component analysis, hierarchical clustering analysis, and absolute principal component scores-multiple linear regression, anthropogenic sources (mining and agricultural activities) contributed most to Zn, Pb, Cr, Cd, Cu, and Ni, with contribution rates of 89.14, 82.32, 74.46, 72.12, 68.52, and 61.02%, respectively. Natural sources contributed most to Mn, with a contribution rate of 83.07%. Unidentified sources contributed most to As, with a contribution rate of 47.27%.

Blending Electrostatic Spinning Fabrication of Superhydrophilic/Underwater Superoleophobic Polysulfonamide/Polyvinylpyrrolidone Nanofibrous Membranes for Efficient Oil-Water Emulsion Separation.

The scarcity of water resources has led to widespread interest in the treatment of oily wastewater. This study prepared a novel superhydrophilic/underwater superoleophobic polysulfonamide (PSA)/polyvinylpyrrolidone (PVP) nanofibrous membrane through electrostatic spinning for efficient oil-water emulsion separation. The surface morphology, fiber diameter distribution, wettability properties, and oil-water emulsion separation performance of the membranes were investigated. Results showed that the addition of PVP increases the diameter of the fibers, which led to a loose, large, porous structure and improved the permeability of the membranes. A high pure-water flux of 2057 L·m-2·h-1 was obtained for membranes with PVP addition of 3 wt%, providing an 835% increase in pure-water flux compared with a pure PSA nanofibrous membrane (220 L·m-2·h-1). For n-hexane-in-water emulsions, the optimum membrane obtained a high separation efficiency of 99.7%, in which flux was 1.5 times greater than that of the pure PSA nanofibrous membrane. Moreover, the optimum membrane exhibited good recycling stability and solvent resistance. The as-prepared PSA/PVP nanofibrous membrane displayed high permeability, an outstanding rejection rate, resistance to organic solvents, and reusability for oil-water separation, providing great potential in practical membrane separation applications.

Solar-Assisted Superhydrophobic MoS2/PDMS/MS Sponge for the Efficient Cleanup of Viscous Oil.

Industrialization releases many high-viscosity oil pollutants into the environment, requiring a hydrophobic recyclable oil-absorbing material. Therefore, a self-heating and superhydrophobic melamine sponge (MS) by connecting polydimethylsiloxane (PDMS) was coated with functionalized molybdenum disulfide (MoS2) nanosheets on a three-dimensional microstructure of a commercial MS (MoS2/PDMS/MS) via a simple and low-cost dip-coating method. The prepared sponge showed a water contact angle of 151.8°, indicating that the modified sponge exhibited superhydrophobicity. Due to the addition of MoS2, the modified sponge can convert light into heat, and its surface could be heated to 59.7 °C within 30 s. Because of the excellent MoS2/PDMS/MS photothermal performance, the sponge could decrease the viscosity of the high-viscosity oil, absorbing the high-viscosity oil efficiently. After simultaneous thermal analysis and repeated compression tests, the modified sponge exhibited high thermochemical stability, mechanical property, and reusability. This superhydrophobic multifunctional sponge shows excellent potential for high-viscosity oil absorption.

Micellization Transformations of Sodium Oleate Induced by Gas Nucleation.

The interfacial properties of surfactant solutions are closely related to the micellization of surfactants. Temperature, salt type and concentration, pH, and other parameters affecting the micellization of surfactants have all been extensively investigated previously. However, the effect of dissolved gas on surfactant micellization and associated interfacial properties' transformations is not completely understood yet. In this study, sodium oleate (NaOl) was chosen as the research object, and the role of gas/gas nucleation in NaOl micellization was systematically investigated. The results indicated that the solution changed to be more turbid and the dissolved oxygen content increased after NaOl solutions were subjected to compression-decompression treatments. Meanwhile, the surface tension of the NaOl solution was altered, which was more pronounced when the concentration of NaOl was close to the critical micelle concentration. Given that the surface tension was a good indicator of the assembly and distribution state of the soluble monomers and insoluble micelles of NaOl, interactions between nucleated bubbles originating from the gas nucleation and NaOl molecules were unveiled through the analysis of the size distribution and zeta potential of sub-micro- and nanoscale particles in bulk solutions. Finally, possible micellization models of NaOl molecules, fully considering the role of gas/gas nucleation, were proposed under varying NaOl concentration conditions.

The integrated production of ultrathing-C3N4and membrane assisted by edible syrup for the sustained photocatalytic treatment of Cr(VI) and tetracycline.

The exfoliation of bulk raw graphitic carbon nitride (g-C3N4) by edible glucose syrup to produce ultrathing-C3N4nanosheets in concentrations of up to 0.2 mg ml-1was achieved. Detailed characterization through TEM, AFM, FT-IR, XRD, Raman and TGA confirmed the formation of ultrathin structure and improved properties. Compared to rawg-C3N4, the prepared thing-C3N4layers exhibited a 18-fold enhancement in Cr(VI) reduction and a 3-fold enhancement in tetracycline hydrochloride degradation, which is ascribed to their larger specific surface area and more exposed active sites. The layeredg-C3N4membrane was constructed via direct vacuum filtration. The layer-stackedg-C3N4nanosheet membrane exhibited an excellent and sustained photocatalytic performance as the prepared thing-C3N4layers could maintain a layered lamella after stacking in filtration process. The recyclable synthesis of ultrathing-C3N4layers and layer-stackedg-C3N4membrane by our method provides a sustainable strategy to pollution treatment by 2D materials.

The efficient biomineralization and adsorption of cadmium (Cd2+) using secretory organo-biominerals (SOBs) produced by screened Alcaligenes faecalis K2.

Cadmium-contaminated wastewater has attracted increasing concerns due to its non-biodegradable properties and high toxicity. To explore eco-friendly and economically feasible strategies, the screened Alcaligenes faecalis K2 were employed for the biomineralization and recovery of Cd2+ from wastewater while producing considerable secretory organo-biominerals (SOBs) as bioadsorbents. At 75 mg/L Cd2+ exposure, 85.5% of Cd2+ was removed by K2, 43.0% of which was fixed in the granular SOBs. SOBs were convenient for separating from the solution. The adsorption capacity of granular sorbent made from SOBs was verified to be greater than 77.1 mg/g. Practically, 89.5% of 75 mg/L of Cd2+ could be stably removed while ereK2 continuously generated SOBs in a moving-bed biofilm reactor (MBBR). To sum up, the production of bioadsorbents can be achieved by K2, while removing Cd with live microorganisms, which was conducive to making full use of materials and improving Cd removal efficiency.

The response of microbial community structure and sediment properties to anthropogenic activities in Caohai wetland sediments.

This study aimed to investigate the response of sediment microbial communities (including bacteria and archaeal groups) in Caohai Lake to anthropogenic activities. The sediment samples were collected from the regions with high anthropogenic interference and low anthropogenic interference. Their physicochemical properties and enzyme activities were analyzed, and the bacterial and archaeal communities were investigated using high-throughput sequencing technology. The results showed that the physicochemical characters changed by anthropogenic activities were the important factors that influenced enzyme activities, alpha diversity, key functional taxa, and community structure. And the impact of anthropogenic activities on microbial communities might follow a non-linear pattern. Furthermore, few significant differences of alpha indices between the high and low disturbed areas, but clear differences of microbial community composition analysis and beta-diversity analysis were observed. The hypothesis was proved that the intensity of anthropogenic impacts in Caohai had not reached the potential thresholds. The best distinguish biomarkers between the two areas and the most related key nodes among the network did not always have a high microbial abundance. The anthropogenic activities might influence the microbial community by affecting a small number of the key taxon in the ecological network. These findings provided a valuable understanding of how sediment microorganisms respond to anthropogenic activities in Caohai Lake.

Synergistic degradation of pyrene by Pseudomonas aeruginosa PA06 and Achromobacter sp. AC15 with sodium citrate as the co-metabolic carbon source.

Two pyrene-degrading strains, Pseudomonas aeruginosa PA06 and Achromobacter sp. AC15 were co-incubated in equal proportions as a microbiological consortium and could enhance the degradation of pyrene. The enzymatic activities of the catechol 1,2-dioxygenase (C12O) and 2,3-dioxygenase activities (C23O) were produced complementary expression by P. aeruginosa PA06 and Achromobacter sp. AC15, respectively. Meanwhile, results showed that pyrene degradation was sufficiently promoted in the presence of sodium citrate as a co-metabolic carbon source, likely a result of enhanced biomass and biosurfactant production. The optimized dosage and ideal initial pHs were 1.4 g L-1 and 5.5, respectively. We also analyzed the rate constant of pyrene degradation, cell growth, and enzyme activity. Results show that P. aeruginosa PA06 had a better effect than Achromobacter sp. AC15 in bacterial growth. However, the C23O or C12O activity produced by Achromobacter sp. AC15 continued at a similar or even faster than that of P. aeruginosa PA06. The mixed bacteria had a better effect than any single bacteria, suggesting the strains worked synergistically to enhance the degradation efficiency. In the co-metabolism system of 600 mg/L pyrene and 1.4 g/L sodium citrate, pyrene degradation reached 74.6%, was 1.57 times, 2.06 times, and 3.89 times that of the mix-culture strains, single PA06 and single AC15 without sodium citrate, respectively. Overall, these findings are valuable as a potential tool for the bioremediation of high-molecular-weight PAHs.

Removal of tetracycline from an aqueous solution using manganese dioxide modified biochar derived from Chinese herbal medicine residues.

Biochar (BC) derived from Chinese herbal medicine residues has been investigated for its performance as a potential adsorbent in tetracycline (TC) removal. In the present study, a chemical co-precipitation method was carried out to prepare manganese dioxide modified biochar (Mn-BC) to increase its sorption capacity. The properties of the modified biochar were characterized for further enhancing TC removal from an aqueous solution. Mn-BC was successfully synthesized and resulted in a much higher specific surface area, total pore volume and pore diameter. The sorption kinetics of TC on Mn-BC was described by the pseudo-second-order model. The sorption data of Mn-BC were fitted by Langmuir and Freundlich models. The study findings revealed a maximum adsorption capacity of Mn-BC (1:10) to TC was up to 131.49 mg/g. The adsorption process was endothermic and spontaneous. The degradation of TC was further enhanced by MnO2 acting as an oxidizer on Mn-BC. Overall, the modified biochar derived from Chinese herbal medicine residues is a superior alternative for the removal of TC from an aqueous solution.

The behaviors of Microcystis aeruginosa and microcystins during the Fe2+/persulfate (PS) preoxidation-coagulation and flocs storage period.

The frequent occurrence of toxin-producing cyanobacteria blooms driven by anthropogenic eutrophication has become a major threat to aquaculture ecosystems worldwide. In this study, the behavior of M. aeruginosa cells during flocs storage period of 6 days was first investigated after pre-oxidation and coagulation of Fe2+/PS. Fe2+/PS achieved a superior removal efficiency of 90.7% for OD680 and 90.4% for chl-a. The contents of extracellular MCs in the pre-oxidation and coagulation system were significantly (P < 0.05) lower than those in the control. A significant (P < 0.05) difference in intracellular protein between the control and the coagulated systems was observed. Three-dimensional fluorescence excitation emission matrix (EEM) was employed to investigate the variations in extracellular organic matter (EOM) during flocs storage. The results indicated the presence of four peaks, representing protein-like substances, intermediate dissolved microbial metabolites, fulvic and humic-like compounds in the Fe2+/PS process. And the intensities of four peaks were all decreased in the Fe2+/PS system compared to those in the control. A low level of accumulated residual Fe of 0.28 mg/L was observed without posing potential environmental risk. The results showed that the M. aeruginosa cells were under stressful conditions after 3-d storage due to the decomposition of extracellular polymeric substances (EPSs) and the insufficient supply of nutrients. However, SEM results indicated that no significant alteration in cell morphology was observed. Therefore, with high removal of M. aeruginosa, low MCs concentrations, and trivial cell damage, the Fe2+/PS preoxidation-coagulation was proved to be an environmental-friendly method for cyanobacteria removal without yielding serious secondary pollution. This work will contribute to better understanding and managing the cyanobacteria-laden aquaculture water after pre-oxidation and coagulation.

Binding of Hg to preformed ferrihydrite-humic acid composites synthesized via co-precipitation and adsorption with different morphologies.

Iron (hydr)oxide-natural organic matter (NOM) colloids, the dominant components of soil, usually occur in varied circumstances and may affect Hg transport and fate in soil. This study aims to reveal the Hg binding to preformed composites rather than only focusing on Hg retention by iron (hydr)oxides in the presence of NOM. Ferrihydrite-humic acid (FH-HA) is chosen as a representative composite, and the effect of the complexation method and FH morphology on Hg binding to various composites is evaluated. Three types of composites are developed: a dense coprecipitated composite (p-d-f), a gel-like adsorbed composite (a-g-f) and a dense adsorbed (a-d-f) composite. Batch sorption and stirred-flow kinetic tests together with surface property analysis and modern spectral analyses are carried out to explore the binding behavior of Hg to the three composites and clarify the interactions in the ternary systems of FH-HA-Hg. The results show that the Hg sorption isotherms all fit well with the Langmuir model, and the maximum sorption capacities follow the order a-g-f> a-d-f > p-d-f, implying that the adsorbed composite is more favorable than the coprecipitated composite for Hg binding and a gel morphology is more beneficial than a dense morphology. The stirred-flow experiments show that the adsorbed composite has a small advantage in Hg sorption compared to the coprecipitated composite and that the gel-like composite can adsorb more Hg at a faster rate than the dense composite. Both FH and HA participate in Hg sorption, and FH-HA-Hg complexes are speculated to form. These findings are helpful to better understand the mobility and fate of Hg in soils, as well as the associated dynamic model for predicting Hg behavior in the environment where the iron (hydr) oxide-NOM composites are pre-existed.

Synergistic effects and kinetics of rGO-modified TiO2 nanocomposite on adsorption and photocatalytic degradation of humic acid.

Graphene oxide was prepared using the modified Hummers method and reduced graphene oxide (rGO) - titanium dioxide (TiO2) nanocomposite was synthesised using the one-step hydrothermal treatment. The synergistic effects on adsorption and photocatalytic properties of the rGO-TiO2 nanocomposite for the humic acid removal were systematically investigated. The results of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Raman and infrared (IR) spectroscopy indicate that GO was partially reduced to reduced graphene oxide (rGO) in the hydrothermal synthesis process and anatase TiO2 nanoparticles uniformly grew on the surface of rGO. The photoelectron and photohole generated under visible light irradiation were effectively separated on the surface of rGO-TiO2. The rGO-TiO2 nanocomposite exhibited higher photocatalytic activity as a result of the synergistic effects of surface functional groups for adsorption and the excellent conductivity for photocatalytic reaction. The effect of rGO-TiO2 nanocomposite dosage, light intensity and system temperature on the removal of humic acid solution was investigated. The results show that the removal efficiency of humic acid increased with system temperature and light intensity. When the dosage of rGO-TiO2 nanocomposite was 1.2 g/L, the temperature, the light intensity and the pH of this system was 303 K, 4.37 Wm-2 and 7, respectively, the removal efficiency of humic acid reached 88.7% under visible light irradiation.

Bioelectricity generation by wetland plant-sediment microbial fuel cells (P-SMFC) and effects on the transformation and mobility of arsenic and heavy metals in sediment.

Two wetland plant-sediment microbial fuel cell systems (PSM1 and PSM2) and one wetland sediment microbial fuel cell system (SM) were constructed to investigate their electricity production performance and the simultaneous migration and transformation of arsenic and heavy metals in sediment and overlying water, arsenic and heavy metals uptake by plants. The bioelectricity generation was monitored for 175 days, and sediment samples were collected at three time points (64, 125 and 200 days) for the analysis. The results showed that plants improved the efficiency of the electricity production by the fuel cell system. The average output voltage was: PSM1 (0.32 V) > PSM2 (0.28 V) > SM (0.24 V)(P ≤ 0.05).The electricity production of the electrodes and the introduction of plants affected the mobility and transformation of As, Zn and Cd in the sediment, which contributed to their stability in the sediment and reduced the release of these metals into the overlying water column. The bioelectricity production process affected the bioavailability of arsenic and heavy metals in the sediment and attenuated metal uptake by plants, which indicated the potential for remediation of arsenic and heavy metals pollution in sediment.

Actinobacterial community in Shuanghe Cave using culture-dependent and -independent approaches.

Karst caves, considering to be the "arks" of biodiversity, often contain high levels of endemism. In the present study, the actinobacterial community in Shuanghe Cave, the longest cave in Asia, was analyzed for the first-time using culture-dependent and -independent (16S rRNA amplicon sequencing) approaches. The amplicon sequencing analysis revealed a broad taxonomic diversity in Shuanghe Cave, including 19 phyla (predominantly Actinobacteria) and 264 different genera. While the culture-dependent method got the unrepresentative but supplemental result, a total of 239 actinomycetes were isolated and were identified to seven genera based on culture features and 16S rRNA tests. Among the three habitats (soil, rock soil, and bat guano), the dominant phyla did not differ significantly, while the dominant genus community varied among different habitats, and the richness in soil and rock soil samples was higher than that in bat guano. Furthermore, 16 isolate strains showed antimicrobial activity, especially, the strain S142 (Streptomyces badius) and S761 (Actinoplanes friuliensis) exhibited the most promising activity against various pathogens. Overall, this work showed the abundant bacterial diversity and the antimicrobial potential of the isolates from the Shuanghe Cave.

Speciation and Bioavailability of Metals in Sediments from a Stream Impacted by Abandoned Mines in Maoshi Town, Southwest of China.

The speciation of metals in surface sediments, as well as metal concentrations in muscle and liver of sharpbelly Hemiculter leucisculus from a stream near the Mo-Ni polymetallic mines in Maoshi town were investigated. The results indicated that metal concentrations were generally highest in the most upstream sampling location that is closest to the former mine operation. The total concentrations of Mn in sediments were higher than other metals. The Cr was mainly associated with residual fraction, while the order of bioavailability of metals (sum of the concentrations of exchangeable, reducible, and oxidizable fractions) was as follows: Cd (89.95%) > Mn (82.32%) > Ni (45.58%) > Mo (29.39%) > Hg (29.23%) > As (22.60%) > Pb (17.38%) > Cr (6.21%). The Cd concentration in muscle of H. leucisculus exceeded the permissible limit which indicated that the fish from this area are not safe for human consumption. The potential ecological risks of Cd cannot be ignored in this study area.

Removal of humic acid from aqueous solution using polyacrylamide/chitosan semi-IPN hydrogel.

In this study, we provide the first documented removal of humic acid (HA) from aqueous solution using polyacrylamide/chitosan (PAAm/CS) semi-IPN hydrogel. The prepared semi-IPN hydrogel was characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The factors effecting HA adsorption performance were individually tested, including initial pH, ionic strength, contact time, initial HA concentration, and temperature. The results indicated that semi-IPN hydrogel was successfully fabricated and can be applied in a wide pH range, from 3 to 9. Low ionic strength effectively enhanced the adsorption capacity. As the ionic strength increased, this enhancement was less obvious but still positive. The adsorption kinetics were fitted to a pseudo-first-order kinetic model, and the adsorption isotherm was described using the Sips isotherm model. The HA adsorption capacity increased with increasing temperature. The maximum adsorption capacity has the potential to attain 166.30 mg g-1, based on the Sips isotherm at 25 °C. Experiments demonstrated that the HA adsorption process can be primarily attributed to electrostatic interactions, and hydrogen bonding was also involved. Facile synthesis and good adsorptive performance indicate that semi-IPN hydrogel can be used for removing HA from water.

Antioxidative responses of Pseudomonas fluorescens YZ2 to simultaneous exposure of Zn and Cefradine.

Binary pollution of both heavy metals and antibiotics has received increasing attentions for their joint effects of eco-toxicity and health hazards. To reveal the effects of mixtures of different pollutants on bacterial antioxidant response system, Pseudomonas fluorescens ZY2, a new strain isolated from swine wastewater, was chosen to determinate growth (bacterial density OD600), reactive oxygen species (ROS) concentration, protein concentration and superoxide dismutase (SOD) activity under exposure treatments of Zn, Cefradine or Zn + Cefradine. Bacterial densities of all the treatment groups increased significantly over the incubation time, but those containing pollutant addition were slightly lower than the control at different times of incubation. Both ROS concentration and SOD activity increased first and then decreased (p < 0.01) over time, which was opposite to the protein concentrations (p < 0.01), showing a much significant increase by Cefradine alone. With Zn concentration increasing from 40 to 160 mg/L, the intracellular SOD activity increased as a response to the improvement of ROS (p < 0.05), while the balance between ROS and SOD was broken down due to the disproportionate change of total SOD activity and ROS concentration, the bacterial densities therefore decreased for the weak resistance. With the combined treatment of Zn (200 mg/L) and Cefradine (1 mg/L), though the toxicity of Zn caused a much significant increase of ROS, the bacterial resistance was further improved showing a more significant increase of total SOD activity and the bacterial densities therefore increased bacterial growth. Zn concentration also affected the protein synthesis. Either single or binary stress induced the bacterial resistance by regulating SOD activity to eliminate ROS. All results of the bacterial oxidant stress, SOD response and protein synthesis in the combined treatment groups were more complicated than those in single treatment groups, which depended on the properties of the single treatment as well as the interaction between the two treatments upon bacterial activity. For P. fluorescens ZY2, the mediation of SOD activity to eliminate ROS in response to the combined exposure to Zn and Cefradine was first revealed as one of the co-resistance mechanisms, which is informative to further understanding the risk of antibiotics resistant bacteria to human and environmental health more accurately.