A review of passive acid mine drainage treatment by PRB and LPB: From design, testing, to construction.

An extensive volume of acid mine drainage (AMD) generated throughout the mining process has been widely regarded as one of the most catastrophic environmental problems. Surface water and groundwater impacted by pollution exhibit extreme low pH values and elevated sulfate and metal/metalloid concentrations, posing a serious threat to the production efficiency of enterprises, domestic water safety, and the ecological health of the basin. Over the recent years, a plethora of techniques has been developed to address the issue of AMD, encompassing nanofiltration membranes, lime neutralization, and carrier-microencapsulation. Nonetheless, these approaches often come with substantial financial implications and exhibit restricted long-term sustainability. Among the array of choices, the permeable reactive barrier (PRB) system emerges as a noteworthy passive remediation method for AMD. Distinguished by its modest construction expenses and enduring stability, this approach proves particularly well-suited for addressing the environmental challenges posed by abandoned mines. This study undertook a comprehensive evaluation of the PRB systems utilized in the remediation of AMD. Furthermore, it introduced the concept of low permeability barrier, derived from the realm of site-contaminated groundwater management. The strategies pertaining to the selection of materials, the physicochemical aspects influencing long-term efficacy, the intricacies of design and construction, as well as the challenges and prospects inherent in barrier technology, are elaborated upon in this discourse.

5-Iodotubercidin inhibits SARS-CoV-2 RNA synthesis.

Coronavirus disease 2019 (COVID-19) is a newly emerged infectious disease caused by a novel coronavirus, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The rapid global emergence of SARS-CoV-2 highlights the importance and urgency for potential drugs to control the pandemic. The functional importance of RNA-dependent RNA polymerase (RdRp) in the viral life cycle, combined with structural conservation and absence of closely related homologs in humans, makes it an attractive target for designing antiviral drugs. Nucleos(t)ide analogs (NAs) are still the most promising broad-spectrum class of viral RdRp inhibitors. In this study, using our previously developed cell-based SARS-CoV-2 RdRp report system, we screened 134 compounds in the Selleckchemicals NAs library. Four candidate compounds, Fludarabine Phosphate, Fludarabine, 6-Thio-20-Deoxyguanosine (6-Thio-dG), and 5-Iodotubercidin, exhibit remarkable potency in inhibiting SARS-CoV-2 RdRp. Among these four compounds, 5-Iodotubercidin exhibited the strongest inhibition upon SARS-CoV-2 RdRp, and was resistant to viral exoribonuclease activity, thus presenting the best antiviral activity against coronavirus from a different genus. Further study showed that the RdRp inhibitory activity of 5-Iodotubercidin is closely related to its capacity to inhibit adenosine kinase (ADK).

Enhanced degradation of petroleum hydrocarbons by immobilizing multiple bacteria on wheat bran biochar and its effect on greenhouse gas emission in saline-alkali soil.

In this study, an immobilization method for forming and keeping dominant petroleum degradation bacteria was successfully developed by immobilizing Pseudomonas, Acinetobacter, and Sphingobacterium genus bacteria on wheat bran biochar pyrolyzed at 300, 500, and 700 °C. The removal efficiency indicated that the highest TPHs (total petroleum hydrocarbons) removal rate of BC500-4 B (biochar pyrolyzed at 500 °C with four kinds of petroleum bacteria) was 58.31%, which was higher than that of BC500 (36.91%) and 4 B (43.98%) used alone. The soil properties revealed that the application of biochar increased the content of organic matter, available phosphorus, and available potassium, but decreased pH and ammonium nitrogen content in soil. Bacterial community analysis suggested that the formation of dominant degrading community represented by Acinetobacter played key roles in TPHs removal. The removal rate of alkanes was similar to that of TPHs. Besides, biochar and immobilized material can also mediate greenhouse gas emission while removing petroleum, biochar used alone and immobilized all could improve CO2 emission, but decrease N2O emission and had no significant impact on CH4 emission. Furthermore, it was the first time to found the addition of Acinetobacter genus bacteria can accelerate the process of forming a dominant degrading community in wheat bran biochar consortium. This study focused on controlling greenhouse gas emission which provides a wider application of combining biochar and bacteria in petroleum soil remediation.

High pyrolysis temperature biochar reduced the transport of petroleum degradation bacteria Corynebacterium variabile HRJ4 in porous media.

Biochar has been widely applied for the remediation of petroleum-contaminated soil. However, the effect of biochar on the transport of petroleum degradation bacteria has not been studied. A typical Gram-positive petroleum degradation bacteria-Corynebacterium variabile HRJ4 was used to study the effect of different biochars on bacterial transport and retention. Results indicated that the addition of biochar in sand was effective for reducing the transport of bacteria and poplar sawdust biochar (PSBC) had a stronger hinder effect than corn straw biochar (CSBC). The hindrance was more evident with pyrolysis temperature of biochar raised from 300°C to 600°C, which was attributed to the increase of specific surface area (309 times). The hindrance effect also enhanced with higher application rate of biochar. Furthermore, the reduction of HRJ4 transport was more obvious in higher (25 mmol/L) concentration of NaCl solution owing to electrostatic attraction enhancement. The adsorption of biochar to HRJ4 was defined to contribute to the hindrance of HRJ4 transport mainly. Combining the influence of feedstocks and pyrolysis temperature on HRJ4 transport, it suggested that specific surface area had the greatest effect on HRJ4 transport, and pore-filling, electrostatic force also contributed to HRJ4 retained in quartz sand column. At last, phenol transportation experiment indicated that the restriction of biochar on HRJ4 enhanced the phenol removal rate in the column. This study provides a theoretical basis for the interaction of biochar and bacteria, which is vital for the remediation of oil-contaminated soil and groundwater in the field.