[Sludge Biochar Modified by B-doped and Its Adsorption Behavior and Mechanism of 1,2-DCA in Water].

Sludge biochar (BC600) and B-doped sludge biochar (BBC600) were prepared with the boric acid doping modified co-pyrolysis method using municipal sludge as precursors, and the materials were structurally characterized by SEM, BET, FTIR, and Zeta potential and static contact angle to investigate the adsorption behavior, mechanism of BC600 and BBC600 on 1,2-DCA in water, and the influencing factors. The results of structural characterization showed that the B element content, specific surface area, and pore volume of biochar increased by 76%, 48%, and 30%, respectively, after the B doping modification; the effect of B doping modification on the surface charge and hydrophobicity of biochar was not significant. The results of adsorption experiments showed that the adsorption of 1,2-DCA by BBC600 was better than that by BC600 due to the larger specific surface area and higher strength of oxygen-containing functional groups of BBC600; the pseudo-first-order kinetic equation could better describe the adsorption of 1,2-DCA by BC600, and the pseudo-second-order kinetic equation could better fit the adsorption of 1,2-DCA by BBC600. The intraparticle diffusion was not the only rate-limiting step affecting the adsorption rate; the biochar material was more dispersed and stable under alkaline conditions, and its oxygen-containing functional groups were deprotonated and had enhanced electron-donating ability, which was beneficial to the adsorption of 1,2-DCA. Humic acid (HA) showed a low concentration-promoting and high concentration-inhibiting effect on the adsorption of 1,2-DCA by BC600, whereas both low and high concentrations of HA showed an inhibitory effect on the adsorption of 1,2-DCA by BBC600. The adsorption of 1,2-DCA by BC600 was inhibited by both low and high concentrations of HA, and HA competed with 1,2-DCA for adsorption; Cl-, SO42-, and NO3- all inhibited the adsorption of 1,2-DCA by biochar, and the degree of inhibition ordered from small to large was Cl-

[Mechanism and Influencing Factors of Increasing Soil Temperature by in-situ Electrical Resistance Heating].

The mechanism and influencing factors of an in-situ thermal remediation using electrical resistance heating were investigated. The effects of electrical current, heating method, rehydration, and negative pressure on soil heating and energy consumption were studied using in-situ electrical resistance heating equipment. The results showed that there were two main mechanisms for soil heating. Firstly, electric energy was converted into heat energy, whereby direct heating of the soil by electricity increased the soil temperature. This mechanism mainly existed in the soil between two electrodes. The second was heat conduction, whereby the soil temperature between the electrodes was the highest, and the heat gradually transferred from the high-temperature soil to the low-temperature soil, such that the temperature of the soil far away from the electrode connection gradually increased. The heating current affected the rate of increase of the soil temperature. The higher the current was, the faster the soil temperature rate of increase was and the lower the unit energy consumption was. Compared with continuous heating, intermittent heating had a slower heating rate and required a longer time to reach the same temperature. However, the energy consumption per unit was low and only 45.2% of that of continuous heating. During the heating process, water should be continuously added to the soil around the electrode to maintain a high current and continuous heating. The negative pressure of extraction was large, the soil heat loss was large, and the unit energy consumption was high. In actual projects, appropriate technological conditions should be selected according to time, cost, and the removal rate as a means of improving the efficiency of the in-situ resistance thermal desorption remediation of contaminated soil, reducing energy consumption, and shortening the time limit.

TolC promotes ExPEC biofilm formation and curli production in response to medium osmolarity.

While a high osmolarity medium activates Cpx signaling and causes CpxR to repress csgD expression, and efflux protein TolC protein plays an important role in biofilm formation in Escherichia coli, whether TolC also responds to an osmolarity change to regulate biofilm formation in extraintestinal pathogenic E. coli (ExPEC) remains unknown. In this study, we constructed ΔtolC mutant and complement ExPEC strains to investigate the role of TolC in the retention of biofilm formation and curli production capability under different osmotic conditions. The ΔtolC mutant showed significantly decreased biofilm formation and lost the ability to produce curli fimbriae compared to its parent ExPEC strain PPECC42 when cultured in M9 medium or 1/2 M9 medium of increased osmolarity with NaCl or sucrose at 28°C. However, biofilm formation and curli production levels were restored to wild-type levels in the ΔtolC mutant in 1/2 M9 medium. We propose for the first time that TolC protein is able to form biofilm even under high osmotic stress. Our findings reveal an interplay between the role of TolC in ExPEC biofilm formation and the osmolarity of the surrounding environment, thus providing guidance for the development of a treatment for ExPEC biofilm formation.