Research progress of novel bio-denitrification technology in deep wastewater treatment.

Excessive nitrogen emissions are a major contributor to water pollution, posing a threat not only to the environment but also to human health. Therefore, achieving deep denitrification of wastewater is of significant importance. Traditional biological denitrification methods have some drawbacks, including long processing times, substantial land requirements, high energy consumption, and high investment and operational costs. In contrast, the novel bio-denitrification technology reduces the traditional processing time and lowers operational and maintenance costs while improving denitrification efficiency. This technology falls within the category of environmentally friendly, low-energy deep denitrification methods. This paper introduces several innovative bio-denitrification technologies and their combinations, conducts a comparative analysis of their denitrification efficiency across various wastewater types, and concludes by outlining the future prospects for the development of these novel bio-denitrification technologies.

Utility and mechanism of magnetic nano-MnFe2O4/MWNT activation for oxidative degradation of tetracycline by persulfate.

A magnetic MnFe2O4/MWNT nanocomposite activated with sodium persulfate (PDS) was investigated for the removal of the widely used antibiotic tetracycline (TC). The best-performing 80 wt.% MnFe2O4/MWNT nanocomposite was screened for catalytic degradation of TC by comparing the catalytic and adsorption processes. The nanocomposite was evaluated using a series of physical characterizations. The effects of catalyst dosage, PDS dosage, temperature, initial pH, and initial concentration of TC on TC removal were investigated. After the reaction for 90 min, the addition of 4 mM PDS to the 80 wt.% MnFe2O4/CNT catalyst at 0.5 g/L degraded 78.85% of TC and 51.97% of TOC at an initial TC concentration of 40 mg/L. The reusability of MnFe2O4/MWNT nanocomposite was evaluated and the structural stability of the material was verified. It was demonstrated that multiple active species (SO4-, ·OH, ·O2-, 1O2) were produced in the MnFe2O4/MWNT/PDS system. The catalytic mechanism was analyzed based on the XPS results. Total organic carbon (TOC) measurement indicated partial TC had completely mineralized. The presumable degradation pathway of TC was proposed according to intermediate products by the LC-MS method.

Hypoxic preconditioning neural stem cell transplantation promotes spinal cord injury in rats by affecting transmembrane immunoglobulin domain-containing.

OBJECTIVE: To explore the effects of hypoxic preconditioning neural stem cell (P-NSC) transplantation on rats with spinal cord injury (SCI). METHODS: After identification, the NSCs were treated with hypoxic preconditioning. The NSCs migration was detected by Transwell method. RT-qPCR was used to detect the mRNA levels of HIF-1α, CXCR4 in NSC. The secretion of representative neurotrophic factors (VEGF, HGF, and BDNF) was checked by Western blot. Forty-six SCI rats were randomly divided into three experimental groups: SCI group (PBS injection, n = 10); N-NSC group (NSC atmospheric normoxic pretreatment injection, n = 18); and P-NSC group (NSC 's hypoxic preconditioning injection, n = 18). The sham operation group was also included (rats underwent laminectomy but not SCI, n = 10). The recovery of hindlimb motor function was evaluated by BBB score. The level of spinal cord inflammation (IL-1ß, TNF-α, and IL-6) was determined by ELISA. Western blot was used to detect the content of TMIGD1 and TMIGD3 in spinal cord. RESULTS: Compared with the N-NSC group, the number of NSC-passing membranes in the P-NSC group increased with the increase of the culture time (p < 0.05). Compared with N-NSC, P-NSC had higher levels of VEGF, HGF, and BDNF after 1 week of culture (p < 0.05). The BBB score of the P-NSC group was significantly higher than that of the N-NSC group at 7 and 28 days (p < 0.05). Compared with the SCI group, the levels of TNF-α, IL-1ß, and IL-6 were significantly reduced after NSC treatment, and the P-NSC group was lower than the N-NSC group (p < 0.05). Compared with the SCI group, the levels of TMIGD1 and TMIGD3 increased. Compared with the N-NSC group, and the levels of TMIGD1 and TMIGD3 increased in the P-NSC group (p < 0.05). CONCLUSION: P-NSC administration could improve SCI injury, and the levels of TMIGD1 and TMIGD3.

RETRACTED: Preparation of molecularly imprinted metal-organic frameworks by in situ self-assembly template strategy for selective adsorption of antibiotics.

This article has been retracted: please see Elsevier Policy on Article Withdrawal ( https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Authors. The corresponding author informed the journal that there were severe problems with the testing instrument that rendered the subsequent conclusions invalid. The authors apologise for any inconvenience caused.

Removal of Pb (II) from aqueous solution by sulfur-functionalized walnut shell.

Heavy metal lead poses a great threat to organisms and the environment; the removal of lead has drawn more and more attention in recent years. In this paper, the sulfur-containing functional group was grafted onto the walnut shell with xanthate to synthesize a low-cost biosorbent (SWM) for the removal of lead in water. The synthesized adsorbent was characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Brunner-Emmet-Teller (BET). The effects of pH, adsorbent dosage, contact time, initial Pb (II) concentration, and temperature on adsorption were investigated, and the adsorption properties of walnut shells before and after modification were compared. Moreover, adsorption kinetics, adsorption isotherms, and adsorption thermodynamics were studied. The sulfur-containing functional group was confirmed to be successfully grafted onto the walnut shell. The results showed that the adsorption performance of SWM was much better than the unmodified walnut shell due to complexation by sulfur-containing functional group and ion exchange. The Pb (II) adsorption onto SWM was found to follow Temkin isotherm model and has a good correlation with the pseudo-second-order kinetic model. In addition, the adsorption process was spontaneous and exothermic. All the results showed that the high adsorption performance and low cost of SWM make it a potential biosorbent in the treatment of lead-contaminated water.