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This study discussed the mechanism of Fe-modified biochar (FeBC) derived from rice straw biochar (BC) as an adsorbent for removing Cr(VI) from aqueous solution and assessed its applicability in actual industrial wastewater. The Cr(VI) removal percentage increased with the FeBC dose, which achieved a removal of 99.5% at 8.0 g/L FeBC. Increasing the solution pH from 2 to 10 slightly reduced Cr(VI) adsorption by 6.6%. Coexisting ions such as Ca2+, Na+ and Cl− inhibited the removal of Cr(VI); the removal rate decreased to 60% at their concentration of 0.25 mol/L. The adsorption isotherm and kinetics were better described by the Langmuir isotherm and pseudo-second-order kinetic models, respectively. Through scanning electron microscopy with energy dispersive X-ray, the Brunauer–Emmett–Teller method, Fourier transform infrared, X-ray diffraction and X-ray photoelectron spectroscopy, the analysis revealed that FeBC with iron oxides loaded onto its surface had more active sites than BC; the surface functional groups changed; the removal of Cr(VI) by FeBC was mainly attributed to electrostatic adsorption; the redox reaction of Cr, and Fe loaded onto BC enhanced Cr(VI) reduction process. FeBC showed a good removal performance on actual industrial wastewater with the concentration of both total Cr and Cr(VI) meeting the integrated wastewater discharge standard of China.

The Yangtze River Delta is the most populous and economically active region in China. Studying the reduction in CO2 emissions in this region is of great significance in achieving the goal of “peak carbon and carbon neutrality” in China. In this study, the Tapio decoupling and extended STIRPAT models were used to study the differences in provincial CO2 emissions characteristics and influencing factors in the Yangtze River Delta from 2001 to 2019. The results show that the growth rate of CO2 emissions was slower than that of economic development, which means that CO2 emissions and economic growth were in a state of weak decoupling. As found by ridge regression, the same factor has different impacts on CO2 emissions among provinces. The differences in these influencing factors were mainly caused by the imbalance of development in the Yangtze River Delta. Nine development scenarios were set out to predict the future trend of CO2 emissions based on economic development and carbon emissions technology using the extended STIRPAT model. It was found that low-carbon-emissions technology is conducive to controlling CO2 emissions in the Yangtze River Delta. In that case, the CO2 emissions would peak in 2029 at 1895.78~1908.25 Mt. Compared with the low-carbon-emissions scenarios, both the medium- and high-carbon-emissions scenarios are not conducive to achieving a carbon peak, with a 2~5-year delay in peak time and increasing emissions by 3.69~7.68%. In order to reduce the Yangtze River Delta’s CO2 emissions and pass the peak emissions as soon as possible, it is essential to not only optimize the energy structure, upgrade industries and promote the coordinated development of low-carbon technologies, but also promote emissions reduction in the transportation and construction fields and advocate for a low-carbon lifestyle among the public.

The application of biochar can affect soil properties and retention of fertilizer nitrogen, but its effects and mechanism on the retention capacity of different forms of nitrogen in soils are still uncertain. In this study, an indoor soil column leaching experiment was conducted using vegetable soil samples with 3% rice husk biochar by mass prepared at 450 °C by pyrolysis and 150 mg N/kg 15N-labeled urea. Adding biochar increased the soil pH, thus alleviating soil acidification caused by fertilizer nitrogen application. It also increased the content of soil organic carbon, total nitrogen and available phosphorus while decreasing that of NH4+-N and NOX−-N(NO3−-Nand NO2−-N) in soils. NOX−-N was the predominant form in the leachate of all treatments, accounting for 63.15–87.90% of the total N loss. Compared to the urea-alone application (the N treatment), incorporating biochar and urea (the RBN treatment) significantly reduced total N and NOX−-N loss by 19.99% and 25.95%, respectively, while showing slight effects on NH4+-N loss. The 15N results show that fertilizer N retention in soil increased by 13.67%, while inorganic 15N leaching decreased by 25.97% after the biochar addition, compared to that in the N treatment. The RBN treatment increased fertilizer N losses in other ways (e.g., organic N leaching, ammonia and NOx volatilization) by 21.72%. Effects of biochar application on other N losses need to be further investigated. Biochar application can reduce the leaching of inorganic 15N and improve fertilizer N retention in the soil. Thus, the potential risk of fertilizer N on the quality of water bodies can be reduced.

Background Anastomotic leakage is one of the most serious postoperative complications of esophageal carcinoma. A new method of anastomosis has been adopted to reduce the incidence of anastomotic leakage. The aim of this study was to verify the safety and effectiveness of this new anastomosis method by comparing with the traditional anastomosis method. Methods A total of 121 patients with esophageal cancer from January 2020 to January 2022 in our department were included. They were divided into two groups according to the different methods of esophagogastrostomy: Side-to-side, end-to-end, embedded anastomosis group (SEE group, n=68) and traditional end-to-side anastomosis group (TE group, n=69). On the 7th day after operation, esophagography was performed to confirm the existence of anastomotic leakage, dysphagia, anastomotic stenosis, and gastroesophageal reflux. Results The incidence of anastomotic leakage in TE group and SEE group were 14.5% and 3.4%, respectively, with statistical significance(p＜0.05). The incidence of anastomotic stenosis in TE group was 21%, while in SEE group it was 3.4%. These differences were statistically significant(p＜0.01). The incidence of reflux in the TE group and the SEE group was 24.2% and 8.5%, respectively, with statistical significance(p＜0.05). The first esophagography after operation showed that the incidence of swallowing disorder was 27.4% in TE group and 57.6% in SEE group. These differences were statistically significant(p＜0.01). However, the incidence of swallowing disorder in TE group and SEE group was 9.7% and 15.3%, respectively, with no significant difference after 3 months (p＞0.05). Conclusion SEE anastomosis is a safe and effective surgical method, which is worthy of clinical application.