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Owing to its effectiveness and being environment-friendly, biochar has been used for adsorbing and immobilizing pollutants in soil in recent years of studies, which is also suitable for manganese pollution in soil caused by manganese mining and processing activities. In this research, alkali-modified pomelo biochar (MBC) was regarded as a soil amendment, and the improvement of soil physicochemical properties and Mn2+ sorption and transport in soil by modifying with MBC were investigated. In incubation experiment, 0–10% (w/w) MBC addition amount significantly improved the physicochemical properties of soil. Due to the amelioration of soil physicochemical properties along with the oxygen-containing functional groups and the developed pore structure of MBC itself, the adsorption capacity of MBC modification soil towards Mn2+ (qe) was enhanced in batch adsorption experiment, and qe increased by 10–108% when MBC ratio grew from 0 to 10% at 300 mg·L−1 Mn2+ solution. In column transport experiment, the Mn2+ retention rate climbed by 13–106% from 0 to 10% MBC addition proportion when adopted the MBC filling way that placed MBC on the soil upper layer, and the reinforced restriction on Mn2+ transport in soil amended with MBC might ascribe to the enhanced qe as well as the reduced saturated hydraulic conductivity. These results proved that MBC effectively augmented adsorption ability and suppressed transport of Mn2+ in soil, which could provide an available mind on prevention and remediation of soil Mn contamination.

With the increase of the azo pigment wastewater, it is necessary to seek an efficient and sustainable treatment method to address issues of damaging water ecosystems and human health. In this work, organic representing azo dye Acid Orange 7 (AO7), heavy metal representing hexavalent chromium (Cr(VI)), and inorganic representing ammonia nitrogen (NH

Electrolysis manganese slag produced in industrial manganese production causes massive leachate containing heavy metal Mn

Periodontal ligament fibroblasts (PDLFs) play a vital role in the period of periodontal regeneration. In addition, studies show that diphenylhydantoin (phenytoin) increases the growth of gingival fibroblasts. If this effect is also present in the periodontal ligament (PDL) fibroblasts, it may be used to regenerate periodontal tissues. Accordingly, this study aimed to compare the effect of phenytoin on the growth rate of gingival fibroblast cells and PDL in the cell culture medium. In this regard, 10 Wistar rats were selected. The gingival specimen was obtained from the area between the upper teeth, and the PDL specimen was obtained from the middle third of the lower teeth root. After transferring the samples to a suitable culture medium for culturing PDL and gingival fibroblasts, each sample was divided into two experimental and control groups. In the experimental group, 20 mg/ml phenytoin dissolved in sodium hydroxide was added to Dulbecco's modified Eagle's medium (DMEM). After 48 hours, fibroblast cell proliferation was assessed through a 1-WST cell proliferation kit by ELISA. The proliferation of gingival fibroblast cells and PDL in both test and control groups were statistically analyzed by the independent t-test. The results showed that the effect of phenytoin on the proliferation of gingival fibroblast cells and PDL fibroblast cells is significant. Also, the proliferation of PDL cells was significantly different from gingival cells in the experimental group (P0.001) and was higher in PDL cells. In general, in this study, it was found that phenytoin in vitro, like in vivo, is able to increase the proliferation of gingival fibroblast cells, and this phenytoin effect is also present in PDL fibroblast cells.

At present, the improvement of nitrate and mixed heavy metals removal in wastewater by microorganism are urgently needed. Previous studies have shown that Pseudomonas hibiscicola strain L1 exhibited Ni(II) removal ability under aerobic denitrification. In this study, the characteristics of the free strain L1, peanut shell biochar (PBC) and further the co-system of strain L1 immobilized on PBC were investigated for the removal of Ni(II), Cr(VI), Cu(II) and nitrate in mix-wastewater. The results illustrated that strain L1 could remove 15.51% - 32.55% of Ni(II) (20-100 mg·L

Agricultural waste was characterized by large quantity and low degree of resource utilization. The peanut shell waste was converted into value-added biochar to alleviate the pollution of dyeing wastewater, which caters to the concept of resource recovery and sustainable utilization. In this work, peroxydisulfate (PDS) could be efficiently activated by biochar obtained by pyrolysis at 700 °C (BC) and Acid Orange 7 (AO7) was rapidly eliminated with 96% removal ratio in 10 min. Meanwhile, BC catalyst performed good stability and reusability. In addition, remarkable removal performance within 40 min (94%) could be achieved in a wide range of pH (3.0-11.0). Through series characterizations, it was found that 700 °C was the critical pyrolysis temperature to prepare material with excellent property mainly attributing to large specific surface area (SSA), followed by high defect structure and rich C-O. It was speculated that radical pathway mainly especially surface-bounded radicals (SO

Aerobic denitrifying bacteria have the potential to remove the co-pollutants Ni(II) and nitrate in industrial wastewater. In this study, aerobic denitrifying bacteria with significant Ni(II) removal efficiency was isolated from the biological reaction tank and named as Pseudomonas hibiscicola L1 strain after 16 S rRNA identification analysis. The removal of ever-increasing Ni(II) and NO3--N wastewater under aerobic conditions by strain L1 was discussed. The experimental results showed that strain L1 removed 84% of Ni(II) and 81% of COD, with the use of 34.8 mg L-1 of nitrogen source and without nitrite accumulation yet. Strain L1 had remarkable activity (OD600 = 0.51-0.56 (p 0.05), and the removal ratios of Ni(II) was enhanced (from 42% to 83% (p

Pseudomonas stutzeri strain XL-2 presented efficient ammonium removal due to heterotrophic nitrification-aerobic denitrification. The modified walnut shell biochar also showed ammonium adsorption due to chemical interaction. The complex of modified biochar and strain XL-2 exhibited excellent synergistic effects on ammonium removal, especially in unfavorable environment. The maximum average ammonium removal rate of the complex was 4.40 mg·L−1·h−1, which was 3.01 times higher than that of pure bacteria and 5.57 times higher than that of biochar. A large number of irregular pores and hydrophilic functional groups promoted the immobilization of strain XL-2 on biochar. Adsorption of ammonium, high specific surface area and release of Mg2+ by biochar enhanced biodegradation of strain XL-2. Approximately 96.34%−98.73% of ammonium was removed in a sequencing batch reactor (SBR) inoculating with the complex of strain XL-2 and biochar, which was much higher than the treatment efficiency of free bacteria in SBR.

Owing to its effectiveness and being environment-friendly, biochar has been used for adsorbing and immobilizing pollutants in soil in recent years of studies, which is also suitable for manganese pollution in soil caused by manganese mining and processing activities. In this research, alkali-modified pomelo biochar (MBC) was regarded as a soil amendment, and the improvement of soil physicochemical properties and Mn

A nitrifying bacterium Acinetobacter sp. AL-6 showed a high efficiency of 99.05% for Mn(II) removal within 144 h when the Mn(II) concentration was 200 mg L-1; meanwhile, 64.23% of NH4+-N was removed. With the Mn(II) concentration increased from 25 to 300 mg L-1, bacterial growth and Mn(II) removal were stimulated. However, due to the electron acceptor competition between Mn(II) oxidation and nitrification reactions, the increase in NH4+-N concentration would inhibit Mn(II) removal. By measuring Mn metabolic form and locating oxidative active factors, it was proved that extracellular oxidation effect played a dominant role in the removal process of Mn(II). The self-regulation of pH during strain metabolism further promoted the occurrence of biological Mn oxidation. Characterization results showed that the Mn oxidation products were tightly attached to the surface of the bacteria in the form of flakes. The product crystal composition (mainly MnO2 and Mn2O3), Mn-O functional group, and element level fluctuations confirmed the biological oxidation information. The changes of -OH, N-H, and -CH2 groups and the appearance of new functional groups (such as C-H and C-O) provided more possibilities for Mn ion adsorption and bonding.

The manganese contamination of groundwater is a global issue that needs to be solved urgently. In this study, a hybrid process between pomelo peel biochar(BC) and Acinetobacter sp. AL-6 (strain AL-6) was established to remove manganese from water. The results showed that microbe-biochar composite had removed 98.19% of manganese (800 mg L−1) within 48 h. Compared with two separate systems (biochar, strain AL-6), the co-system (strain AL-6 and BC composite) had an excellent synergy effect on manganese removal. The average removal rate of manganese in the synergistic system was 14.08 mg L−1 h−1, which was 6.41 times higher than strain AL-6, 3.45 times higher than biochar, and even at 2.24 times their sum. In addition, the scanning electron microscope (SEM) and the bioassay indicated that many strains were attached to biochar and had vigorous biological activity. The FTIR results showed that the functional groups of OH, C O, C O, CH2, and C H played a vital role in removing manganese. And the correlation analysis shows that biochar with strains AL-6 has a highly synergistic effect on manganese removal. Meanwhile, the composite material can maintain excellent manganese removal efficiency under different pH conditions. Besides, in the sequence batch reactor (SBR) inoculating with the microbe-biochar composite, more than 96% of manganese was removed, which far exceeded the treatment efficiency of free bacteria in the SBR. Hence, biochar-immobilized AL-6 has great potential and can be applied to degrade manganese polluted wastewater.

Ammonium pollution caused by human activities threated to eco-environment and the groundwater was polluted by rain and other leaching processes. This study investigated the mechanism and dynamic adsorptive characteristic of ammonium (NH4+-N), which removed by a novel modified biochar (MBC) pyrolyzed from peanut shell. The maximum capacity of unmodified biochar (BC) and modified biochar (MBC) to ammonium absorption could reach 3.83 mg/g and 6.92 mg/g, respectively, indicating that modification would enhance the performance of the adsorbent. Analyzing a batch of experimental data, it can be found that the isothermal absorption was suitable for Sips model and the kinetic adsorption model suitable for quasi-second-order kinetic model, indicating that the adsorptive rate was related to the amount of the adsorption site and dominated by monolayers chemisorption. The characteristics of MBC before and after the process of adsorption showed that ion exchange, electrostatic adsorption and surface complexation were the main factors controlling adsorptive capacity. The dynamic removal performance of ammonium by MBC under different conditions was investigated by column experiments. The experimental data of breakthrough curve fitted the Thomas model well. The maximum adsorptive capacity (kTH = 5.28 × 10–3 L/(mg·h), and qe = 9.02 mg/g) was obtained when the influent concentration reached 30 mg/L, the bed depth 2.1 cm and the inflow rate 1 mL/min. It can be concluded that the MBC was a promising adsorbent which can effectively remove ammonium from groundwater.

Environmental contextIndustrial development has caused the release of hexavalent chromium and nitrates into the environment. Interactions of hexavalent chromium and nitrates with microorganisms are important both for understanding environmental behaviour and for treatment options. Bacterial removal of both chromium and nitrate was optimised in waters relevant to waste streams and the environment. Abstract An isolated strain of the bacterium Stenotrophomonas maltophilia strain W26, is shown to be capable of the simultaneous removal of nitrate and CrVI under aerobic conditions. Notably, 10mg L−1 of CrVI and 500mg L−1 of nitrate were reduced by 92.6% and 85.2%, respectively, by strain W26. Results showed that an excellent denitrification efficiency of 96.0% could be reached at the optimal conditions of a C/N ratio of 10, using a carbon source of trisodium citrate, at pH 7.5, and a nitrate concentration of 500mg L−1. Strain W26 could also effectively remove high concentrations of CrVI (50mg L−1, 93.2%) and nitrate (700mg L−1, 97.4%). By using the N balance analysis, energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS), the denitrification and CrVI transformation processes were verified. CrVI, immobilised on the cell surface by W26, was reduced to CrIII, through interaction with of O=C and N-H groups. This study indicates that the isolated strain W26 has the potential to treat wastewater containing combined nitrate and CrVI contamination.

The interference of toxic heavy metals in the process of microbial aerobic denitrification is a hot issue in industry wastewater treatment in recent years. In this study, a multifunctional aerobic denitrifying bacterium - Pseudomonas aeruginosa G12 isolated from sewage sludge was used to explore the simultaneous removal ability to NO3−-N and Cr(VI) in wastewater by a series of batch experiments. The results showed that G12 could effectively remove NO3−-N (500 mg L−1) and Cr(VI) (10 mg L−1) by 98% and 93%, respectively. Meanwhile, the study found that the strain G12 had the potential to adapt to the complex external environment, including different carbon resources, nitrogen sources, and the coexisting heavy metals (Mn2+ and Cu2+). The strain G12 also had the considerable tolerance to initial NO3−-N (100–700 mg L−1) and Cr(VI) (1–20 mg L−1) concentrations. The instrument analysis methods-Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD), from the molecular level, further confirmed that the strain G12 could remove NO3−-N by aerobic denitrification, and the reduced functional groups (amino group, amide group, hydroxyl group and carboxyl group) on the surface of bacteria could transform Cr(VI) to Cr(III) (mainly CrCl3). This study will offer a promising new microbial resource for nitrogen and Cr(VI) removal in industry wastewater treatment.