Effects of multi-heavy metal composite pollution on microorganisms around a lead-zinc mine in typical karst areas, southwest China.

Heavy metal pollution poses a serious hazard to the soil bacterial community. The purpose of this study is to understand the characteristics of soil heavy metal pollution in lead-zinc mines in karst areas and the response of Pb, Zn, Cd, and As-induced composite pollution to soil microorganisms. This paper selected soil samples from the lead-zinc mining area of Xiangrong Mining Co., Ltd., Puding County, Guizhou Province, China. The soil in the mining area is contaminated by multiple heavy metals such as Pb, Zn, Cd and As. The average levels of Pb, Zn, Cd and As in the Pb-Zn mining soil were 14.5, 7.8, 5.5 and 4.4 times higher than the soil background in this area, respectively. Bacterial community structures and functions were analyzed using 16 S rRNA high-throughput sequencing technology and the PICRUSt method. A total of 19 bacterial phyla, 34 classes and 76 orders were detected in the tested soil. At the phylum level, the Proteobacteria are the dominant flora of the soil in the tailings reservoir area of the lead-zinc mine, respectively GWK1 (49.64%), GWK2 (81.89%), GWK3 (95.16%); and for the surrounding farmland soil, the Proteobacteria, Actinobacteriota, Acidobacteriota, Chloroflexi and Firmicutes are the most abundant in five bacterial groups. RDA analyses revealed that the heavy metal pollution of the lead-zinc mining area has a significant impact on the diversity of soil microorganisms. As the distance from the mining area increased, the heavy metal comprehensive pollution and potential risk value decreased, and the bacterial diversity increased. Additionally, various types of heavy metals have different effects on bacterial communities, and soil heavy metal content will also change the bacterial community structure. Proteobacteria positively related to Pb, Cd, and Zn, therefore, Proteobacteria were highly resistant to heavy metals. PICRUSt analysis suggested that heavy metals significantly affect the metabolic function of microorganisms. Microorganisms might generate resistance and enable themselves to survive by increasing the transport of metal ions and excreting metal ions. These results can be used as a basis for the microbial remediation of heavy metal-contaminated farmland in mining areas.

[Effect of rhGH on JAK2-STAT3 signal pathway after GHR was down-regulated by siRNA in gastric cancer cell].

To investigate the effect of recombinant human growth hormone (rhGH) on JAK2-STAT3 pathway and the growth of gastric cancer cell lines at different GHR expression status, the eukaryotic expression vector targeting human GHR (pGPU6/GFP/Neo-shGHR and pGPU6/GFP/Neo-scramble) was constructed and transfected into MGC803 cells by Lipofectamine 2000. Stable expressive cell lines were obtained by G418 screening. The expression of GHR was analyzed by Western blotting. After being stimulated with rhGH, cell growth was detected by MTT assay. Cell cycle and apoptosis were examined by flow cytometry. The components of JAK2/STAT3 signaling pathway were detected by Western blotting. There is no significant difference of GHR expression between MGC803 and pGPU6/GFP/Neo-scramble-transfected cells (named as MGC803-NC) (P > 0.05). Compared with MGC803, the GHR expression in pGPU6/GFP/Neo-shGHR-transfected cells (named as MGC803-shGHR) decreased significantly (protein decreased 50%). The cells were treated with rhGH at 0, 150 and 300 ng x mL(-1), the growth rate of MGC803 and MGC803-NC increased significantly, PI and the number of G2/M phase cells all increased significantly, and apoptosis decreased significantly. Western blotting revealed that the expression of pJAK2 and pSTAT3 was up-regulated after being treated with rhGH in MGC803 and MGC803-NC cells. In contrast, similar change was not observed in MGC803-shGHR cells. Knockdown of GHR gene may decrease the sensitivity of gastric cancer cells to rhGH, and down-regulating of components of the expression of JAK2/STAT3 signaling pathway may be the potential mechanisms.

Application of membrane separation technology in the treatment of leachate in China: A review.

To comprehensively investigate the application of membrane separation technology in the treatment of landfill leachate in China, the performance of nearly 200 waste management enterprises of different sizes in China were analyzed, with an emphasis on their scale, regional features, processes, and economic characteristics. It was found that membrane separation technologies, mainly nanofiltration (NF), reverse osmosis (RO), and NF + RO, have been used in China since 2004. The treatment capacity of the two most dominant membrane separation technologies, i.e., NF and RO, were both almost 60,000 m3/d in 2018, and both technologies are widely used in landfills and incineration plants. Their distribution is mainly concentrated in eastern and southwestern China, where the amount of municipal solid waste (MSW) is relatively high and the economy is developing rapidly. Membrane separation technology is the preferred technique for the advanced treatment of leachate because more contaminants can be effectively removed by the technology than by other advanced processes. However, the membrane retentate that is produced using this technology-commonly known as leachate concentrate-is heavily contaminated due to the enrichment of almost all the inorganic anions, heavy metals, and organic matter that remain after bioprocessing. An economic cost analysis revealed that the operating cost of membrane separation technology has stabilized and is between 1.77 USD/m3 and 4.90 USD/m3; electricity consumption is the most expensive cost component. This review describes the current problems with the use of membrane separation technology and recommends strategies and solutions for its future use.

Extremely efficient and rapidly adsorb methylene blue using porous adsorbent prepared from waste paper: Kinetics and equilibrium studies.

For the first time, zinc chloride activation method was used to prepare waste paper-based activated carbon in this study. The structure, morphology, surface functional groups and particle size distribution of the activated carbon was study using automatic specific surface area analyzer, FTIR, Boehm titration, X-ray diffraction, SEM and EDS. The specific surface area of the activated carbon is up to 1987 m2/g. Cumulative pore volume is up to 2.586 cm3/g, with micropore volume accounting for 92 %. Methylene blue adsorption performance results shown that the adsorbent has achieved high removal efficiency (99.65 % in 10 min, uptake = 996.5 mg/g), its maximum adsorption capacity has reached 1657 mg/g. The pHpzc of the adsorbent was determined to explore the adsorption mechanism, its results shown that electrostatic adsorption occurs between adsorbents and adsorbents at pH higher than pHpzc (pHpzc = 3.2). Moreover, adsorption mechanism was studied by various isothermal models, thermodynamic models, kinetic models. Redlich-Peterson isotherm model best describes the adsorption experiment, which indicated that the adsorption follows a non-ideal and mixed adsorption mechanism. Methylene blue molecules gone into micropore was the adsorption rate-limiting step, and MB adsorption by the waste paper-based adsorbent was a spontaneous, endothermic and randomly increasing adsorption. Simulated wastewater and regeneration experiments were also used to evaluate the adsorbent's treatment capacity and economic efficiency, and these results indicated that the adsorbent has good decolorization and regeneration ability.

Degradation of refractory organic compounds from dinitrodiazophenol containing industrial wastewater through UV/H2O2 and UV/PS processes.

In this study, refractory organic compounds from dinitrodiazophenol (DDNP) containing industrial wastewater were degraded through two ultraviolet (UV)-based advanced oxidation processes: UV/hydrogen peroxide (UV/H2O2) and UV/potassium persulfate (UV/PS) processes. In both processes, the synergistic effects, operational parameters (i.e., oxidant dosage and initial pH value), and pseudo first-order constant k were systematically studied. Moreover, the reactive oxygen species formed in the UV/H2O2 and UV/PS processes were identified, and the degradation of refractory organic compounds was characterized through UV-visible spectra analysis. The improvement in biodegradability of DDNP industrial wastewater after treatment by different processes was compared. Both the UV/H2O2 (synergistic coefficient F = 61.34) and UV/PS (synergistic coefficient F = 54.85) processes showed significant, highly synergistic effects. The increase in oxidant dosage was beneficial in organic compound removal in both the UV/H2O2 and UV/PS processes, but excessive H2O2 showed a stronger inhibition of the increase in organic compound removal than that in the UV/PS process. In addition, an acidic environment was more conducive to organic compound degradation in the UV/H2O2 process, whereas the initial pH value had less of an influence on the UV/PS process. Under optimal conditions for the UV/H2O2 and UV/PS processes, the CN and COD removal efficiencies were 99.71%, 66.35%, 99.69%, and 70.81%, respectively, and the k values for COD removal were 0.0804 and 0.0824 min-1. Tests to identify reactive oxygen species showed that the hydroxyl radical was the predominant oxidizing species in the UV/H2O2 process, whereas the hydroxyl and sulfate radicals were both identified in the UV/PS process, and the sulfate radical contributed the most to the degradation of organic compounds. In addition, spectrum analysis revealed that the complex structure (e.g., benzene ring, nitro group, and diazo group) of refractory organic compounds from DDNP industrial wastewater was effectively destroyed by the UV/H2O2 and UV/PS processes, and both processes improved the biodegradability (biochemical oxygen demand for 5 days/chemical oxygen demand (BOD5/COD)) of DDNP industrial wastewater from 0.052 to 0.665 and 0.717, respectively. Overall, both the UV/H2O2 and UV/PS processes effectively degraded the refractory organic compounds from DDNP industrial wastewater, and the UV/PS process exhibited a higher organic compound removal efficiency and better applicability.

Comparative study of atrazine degradation by magnetic clay activated persulfate and H2O2.

To effectively remove the endocrine disrupting chemicals (EDCs) in water, Fe3O4 was loaded on the surface of modified sepiolite clay by the method of co-precipitation to catalyze potassium persulfate (K2S2O8) and hydrogen peroxide (H2O2) respectively to generate SO4˙- and ·OH for atrazine (ATZ) removal. The magnetic clay catalyst was characterized by XRD, SEM, N2 adsorption-desorption and isoelectric point. The degradation efficiency of ATZ in the two systems was systematically compared in terms of initial pH, oxidant dosage and oxidant utilization rate. The results revealed that, after 90 minutes, systems with K2S2O8 and H2O2 can remove 65.7% and 57.8% of the ATZ under the given conditions (30 °C, catalyst load: 1 g L-1, initial pH: 5, [ATZ]0: 10 mg L-1, [H2O2]0: 46 mmol L-1, [PDS]0: 46 mmol L-1). The magnetic clay catalyst still maintained good catalytic activity and stability during the four consecutive runs. Based on the quenching experiments, it was demonstrated that the dominant radical species in the two systems were SO4˙-/·OH and ·OH, respectively. However, the degradation efficiency of the two systems presented different responses toward the condition variations; the system with K2S2O8 was relatively more sensitive to solution pH, the oxidant efficiency was generally higher than that of the H2O2 system (except 184 mmol L-1).

Sequential coagulation and Fe0-O3/H2O2 process for removing recalcitrant organics from semi-aerobic aged refuse biofilter leachate: Treatment efficiency and degradation mechanism.

Landfill leachate effluent obtained after semi-aerobic aged refuse biofilter (SAARB) treatment still contains various recalcitrant organics. In this study, a sequential coagulation and Fe0-O3/H2O2 process was developed for treating SAARB leachate. The effects in terms of degradation of recalcitrant organics and the related mechanisms due to the coagulation and Fe0-O3/H2O2 processes were systematically explored and discussed. The results indicated that polymerized ferric sulfate was the most efficient coagulant for treating SAARB leachate where the chemical oxygen demand (COD), UV254, and CN removal efficiencies were 59.60%, 63.22%, and 70.32%, respectively. In the Fe0-O3/H2O2 process under the optimized conditions comprising Fe0 dose = 0.6 g/L, O3 dose = 26.80 mg/min, H2O2 dose = 1.0 mL/L, and reaction time = 20 min, the COD, UV254, and CN removal efficiencies with the coagulated supernatant were 43.39%, 59.47%, and 93.20%, respectively, and the biodegradability (biochemical oxygen demand/COD) improved greatly from 0.06 to 0.34. Analysis of UV-Vis and 3D-EEM spectra indicated that coagulation-resistant substances in the SAARB leachate could be effectively degraded and destroyed by the Fe0-O3/H2O2 process. In the O3/H2O2 environment, Fe0 generated Fe2+ and iron oxides (Fe2O3, Fe3O4, and FeOOH) with homogeneous and heterogeneous catalytic roles against O3/H2O2 to produce reactive oxygen species. Furthermore, Fe(OH)2 and Fe(OH)3 colloids contributed to the removal of organics to some extent via adsorption and precipitation effects. In conclusion, the proposed sequential coagulation and Fe0-O3/H2O2 process is an efficient method for treating recalcitrant organics in SAARB leachates.

Removal of refractory organics in dinitrodiazophenol industrial wastewater by an ultraviolet-coupled Fenton process.

A significant amount of biorefractory organic wastewater is generated during the production of dinitrodiazophenol (DDNP). In this study, ultraviolet light (254 nm) that was coupled with the Fenton (UV-Fenton) process was applied to treat refractory organics in DDNP industrial wastewater. The effects of key parameters (i.e., H2O2 dose, Fe2+ dosage, and initial pH) on the treatment efficacy for DDNP industrial wastewater by the UV-Fenton process was investigated systematically. Alcohol quenching experiments were carried out to identify reactive oxygen species in the UV-Fenton process. The treatment efficacy and degradation characteristics of refractory organics were studied and compared by using control experiments. Increasing H2O2 and Fe2+ doses could lead to improved treatment results to a different extent. A more intense reaction and better treatment results were achieved by using the UV-Fenton process at lower pH conditions. Under optimal conditions of H2O2 dose = 7.5 mL L-1, Fe2+ dosage = 0.05 mM, and initial pH = 5.0, the pseudo-first order constants k for chemical oxygen demand removal and color number removal were 0.18 min-1 and 1.24 min-1, and the chemical oxygen demand and color number removal efficiencies were 74.24% and 99.94%, respectively. The treatment results for the UV-Fenton process were better than other processes under the same conditions, and a significant synergetic effect was observed for the UV-Fenton process. Alcohol quenching experiments indicated that the predominant reactive oxygen species in the UV-Fenton process was the hydroxyl radical (·OH). Because more ·OH was produced, the UV-Fenton process exhibited a much better treatment performance in degrading and destroying organic structures (i.e., benzene rings, -NO2, and -N[double bond, length as m-dash]N-). Furthermore, the biodegradability indicated by the biological oxygen demand/chemical oxygen demand ratio was improved considerably to 0.48 from 0.054. The good treatment performance by UV-Fenton allowed for a more efficient electrical energy consumption compared with the UV and UV-H2O2. This study provides a theoretical reference for DDNP industrial wastewater treatment by using the UV-Fenton process.

An investigation of refractory organics in membrane bioreactor effluent following the treatment of landfill leachate by the O3/H2O2 and MW/PS processes.

In this study, refractory organics in a membrane bioreactor (MBR) effluent were investigated following the treatment of landfill leachate by the ozone combined hydrogen peroxide (O3/H2O2) and microwave-activated persulfate (MW/PS) processes. The treatment efficiency and the transformation characteristics of refractory organics and reactive oxygen species were determined. It was found that an acidic environment and an increase in the O3 dosage improved the organic removal efficiency in the O3/H2O2 process, and the use of H2O2 improved the treatment efficiency, while excessive H2O2 inhibited it. In the MW/PS process, an increase in the PS dosage and MW power greatly improved the treatment efficiency, while an alkaline environment inhibited it. Under the optimized reaction parameters, the O3/H2O2 and MW/PS processes effectively degraded refractory organics (i.e., humic acid and fulvic acid) into components with a smaller molecular weight and simpler structure. The humification, aromaticity, and conjugation of organics in wastewater were greatly reduced. Compared to the O3/H2O2 process, the MW/PS process had a better treatment effect on refractory organics, and there were more low molecular weight organics (<1 kDa) in the treated wastewater. Because O3 is the main selective oxidant in the O3/H2O2 process, a large amount of organic acids were accumulated. A large amount of hydroxyl radicals and sulfate radicals with strong oxidation ability were produced in the MW/PS process, and therefore the combined action of hydroxyl and sulfate radicals can efficiently decompose humus and intermediate organics. Overall, the MW/PS process was more effective in treating the MBR effluent than the O3/H2O2 process. The results of this study provide a reference for the selection of an advanced oxidation process to eliminate refractory organics in landfill leachate.

Study of curative effect of combined therapy in the elderly patients with oral squamous-cell carcinoma / 中华老年医学杂志

0.05).There was significant difference in the 3-year survival rate between A and C group. Conclusions The 3-year survival rate was dramatically increased with combined therapy mainly by cisplatin, the dose of 60～80mg is tolerant for the elderly aged above seventy years, and perioperation complications can be cured.