Search

Adsorption technology is a hot topic in the field of dye removal, and higher adsorption capacity is one of the eternal themes. Ionic dyes account for more than 90% of the literature on dyes adsorption in recent decade. In this article, various physical and chemical mechanisms of dye adsorption are combed in detail, and electrostatic interaction is the major mechanism of ionic dyes adsorption. The key to improving the adsorption capacity is to increase the electrostatic interaction force/surface charge of adsorbents. Moreover, different modification methods to improve the adsorption of ionic dyes by changing the charge properties of adsorbents were reviewed, including grafting functional groups, composite, and adsorbent structural modulation. The practical prospects of each modification method/substance were highlighted and discussed from the perspectives of performance, preparation processes, cost, and toxicity. This review mainly includes (1) the classification and adsorption mechanisms of dyes; (2) types, performance and application prospects of grafted ligands and substances applied for compositing; (3) the performance and limitations of the structural regulation methods; (4) research progresses of amphoteric adsorbents; (5) the prospect of adsorbents development and industrial-scale application. This review attempts to provide a detailed reference for the modification of adsorbents via electrostatic interaction regulation.

This paper is a reanalysis of the Hart-Fuller debate based on the Grudger Informer case, which discusses whether the German court should incorporate morality in determining the validity of laws. Hart proposes that the rule of recognition, customarily practiced by legal officials, is the test of legal validity. Law and morality are therefore not necessarily connected because legal officials have duty to obey the law, represented in the rule of recognition. Fuller claims that law and morality are connected given the fact that extremely unjust laws lose their validity. This paper argues instead that extremely unjust laws cannot be valid still fit in the rule of recognition as the test itself is limited due to political constraint. This is an implication of Hart’s theory that is not directly claimed by Hart.

Far-ranging and improper uses of pharmaceuticals and personal care products (PPCPs) over the last few decades have led to severe water contamination that imposes serious effects on human beings and the ecological system. Therefore, there is an increasing demand for a highly-efficient and environmentally friendly technology for the removal of PPCPs from aqueous solutions. Adsorption technology is an appropriate technology to solve this issue. Carbon-based composites, ranging from modified activated carbon to functionalized biochar, show great potential for this purpose. This review hence elaborates on the environmental occurrences and risks of PPCPs and summarizes the recent progress in removing PPCPs from water using carbon-based adsorbents. The pore structure, relatively large specific surface area (SSA), abundant surface functional groups, highly aromatic structures and the extra excellent characteristics of the cooperative materials contribute to their outstanding adsorption performance. Furthermore, the biochar-clay material is cost effective and more efficient compared to traditional activated carbon regarding the adsorption of PPCPs. Among the emerging adsorbents, graphene and carbon nanotubes composites show superior adsorption ability. Their adsorption mechanisms, such as electrostatic interactions, hydrogen bonding, and pore filling, are discussed in details.

Waste generated by healthcare facilities during the COVID-19 pandemic has become a new source of pollution, particularly with the widespread use of single-use personal protective equipment (PPE). Releasing microplastics (MPs) and microfibers (MFs) from discarded PPE becomes an emerging threat to environmental sustainability. MPs/MFs have recently been reported in a variety of aquatic and terrestrial ecosystems, including water, deep-sea sediments, air, and soil. As COVID-19 spreads, the use of plastic-made PPE in healthcare facilities has increased significantly worldwide, resulting in massive amounts of plastic waste entering the terrestrial and marine environments. High loads of MPs/MFs emitted into the environment due to excessive PPE consumption are easily consumed by aquatic organisms, disrupting the food chain, and potentially causing chronic health problems in humans. Thus, proper management of PPE waste is critical for ensuring a post-COVID sustainable environment, which has recently attracted the attention of the scientific community. The current study aims to review the global consumption and sustainable management of discarded PPE in the context of COVID-19. The severe impacts of PPE-emitted MPs/MFs on human health and other environmental segments are briefly addressed. Despite extensive research progress in the area, many questions about MP/MF contamination in the context of COVID-19 remain unanswered. Therefore, in response to the post-COVID environmental remediation concerns, future research directions and recommendations are highlighted considering the current MP/MF research progress from COVID-related PPE waste.

We establish relations of Gorenstein homological properties of modules and rings linked by a fixed quasi-Frobenius bimodule. Particularly, let $$R\subset S$$ be a strongly separable quasi-Frobenius extension. The left Gorenstein global dimensions and the left finitistic Gorenstein projective dimensions of rings S and R are equal. Moreover, R is left-Gorenstein (Cohen–Macaulay finite, Cohen–Macaulay free) if and only if so is S.

Using a murine collagen-induced arthritis model, we characterized the heterogeneity of synovial CD8

Antibiotic abuse will seriously affect the ecology and environment. Photocatalytic oxidation technology based on carbon nitride (g-C

Currently, serious challenges to drinking water security remain. Toxic chemicals and opportunistic pathogens can trigger a grave health risks even in areas where the water supply system is relative...

From emerging pollutants to emerged threat, researchers are continuously looking for promising technologies for wastewater treatment. Adsorption has been identified as the most convenient approach for treating wastewater at low-cost and with high-efficiency. Recently, graphene and its derivatives have gained heightened attention as novel adsorbents because of their unique molecular structure and outstanding physicochemical properties. Heavy metals, dyes, polycyclic aromatic hydrocarbons (PAHs) and other pollutants, which are widely concerned recently, all show different adsorption behaviors. Numerous functional groups, resonating and delocalized π-electron system of graphene derivatives lead to the formation of various adsorptive interactions i.e., π-π interactions, electrostatic interactions, H-bonding, etc. with these venomous pollutants, and quarantine them in solution. The pristine form of graphene subsidiaries tends to exhibit low sorption efficiency due to high propensity of agglomeration, lack of selectivity, hydrophobicity and difficulty in phase separation after treatment. Therefore, designing of efficient graphene composites through the surface modification with numerous functional groups, polymers or nanoparticles is an ongoing challenge. Complex graphene composites are increasingly reported, but the fate of pollutants and adsorption mechanisms are still far to be fully clarified. This review summarizes the recent progresses in the application of graphene-based adsorbents for eliminating a wide range of organic and inorganic pollutants from wastewater. A critical explanation is provided on the synthesis of graphene adsorbents, systematic adsorption and desorption mechanisms along with their pollutant removal performances under different experimental conditions. A brief perspective on upcoming research needs and challenges involved in the designing of high-quality graphene-based adsorbents are highlighted.

At present, the assessment of photooxidation system mainly focuses on the photodegradation efficiency of target pollutant, lacking of the toxicity assessment in the photocatalysis process. Here, photodecomposition of bisphenol A (BPA) was used to investigate the performance of several cyclodextrin modified photocatalysts. Moreover, the comprehensive toxicity changes of BPA under different photocatalytic oxidation conditions were conducted. The β-cyclodextrin (β-CD) modified photocatalyst, including titanium dioxide (CM-β-CD-TiO2), carbon nitride (CM-β-CD-C3N4) and cadmium sulfide (SH-β-CD-AM/CdS) exhibit high degradation rate and mineralization efficiency of BPA. The highest total organic carbon (TOC) removal of BPA observed in the oxidation system of SH-β-CD-AM/CdS nanoreactor (73.4%). The main oxidation intermediates in these systems were detected, and the comprehension toxicity of BPA and its oxidation intermediates in different system were compared by toxicity estimation software tool (T.E.S.T.) based on quantitative structure-activity relationship (QSAR) prediction. The results show that β-CD can facilitate the photodecomposition of the target contaminant. However, many oxidation intermediates with high comprehensive toxicity, even in the oxidation system with high BPA removal, can still be detected. Therefore, not only decomposition of target contaminant but also the comprehensive toxicity of oxidation intermediates should be regarded as index to evaluate a photocatalysis technology.

In this study, the enhanced trichloroethylene (TCE) degradation performance was investigated by polyvinyl alcohol coated calcium peroxide nanoparticles (PVA@nCP) as an oxidant in Fe(II)-based catalytic systems. The nanoscale iron sulfide (nFeS), having an average particle size of 115.4 nm, was synthesized in the laboratory and characterized by SEM, TEM, HR-TEM along with EDS elemental mapping, XRD, FTIR, ICP-OES, and XPS techniques. In only ferrous iron catalyzed system (PVA@nCP/Fe(II)), TCE degradation was recorded at 58.9% in 6 h. In comparison, this value was increased to 97.5% or 99.7% with the addition of citric acid (CA) or nFeS in PVA@nCP/Fe(II) system, respectively. A comparative study was performed with optimum usages of chemical reagents in both PVA@nCP/Fe(II)/CA and PVA@nCP/Fe(II)/nFeS systems. Further, the probe compounds tests and electron paramagnetic resonance (EPR) analysis confirmed the generation of reactive oxygen species. The scavenging experiments elucidated the dominant role of HO• to TCE degradation, particularly in PVA@nCP/Fe(II)/nFeS system. Both CA and nFeS strengthened PVA@nCP/Fe(II) system, but displayed completely different mechanisms in the enhancement of active radicals generation; hence, their different contribution to TCE degradation. The acidic environment was favorable for TCE degradation, and a high concentration of HCO3- inhibited TCE removal in both systems. Conclusively, compared to PVA@nCP/Fe(II)/nFeS system, PVA@nCP/Fe(II)/CA system resulted in encouraging TCE degradation outcomes in actual groundwater, showing great potential for prolonged benefits in the remediation of TCE polluted groundwater. Graphical abstract.

Environment-friendly treatment process relies on the robustness, durability, and performance of catalysts to drive the development of cutting-edge sustainable technologies for the elimination of refractory contaminants. Herein, nanocomposites prepared from zero-valent Co–Fe encapsulated in nitrogen-containing carbon (N C) nanoparticles (CFNC-30 NPs) derived from CoFe2O4@zeolitic imidazolate frameworks-67 were successfully prepared through pyrolysis integrated with self-reduction, and further utilized as the novel catalysts to degrade 4-chlorophenol (4-CP) by coupling with peroxymonosulfate (PMS). Three optimized parameters (CFNC-30 NPs dosage of 0.089 g L−1, PMS concentration of 1.1 g L−1, and initial pH of 6.6) were obtained via response surface methodology by using the Box–Behnken design model. Benefiting from the larger specific surface area, pore-volume, and existence of abundant hydroxyl groups, CFNC-30 NPs with more available active sites exhibited an excellent efficiency of 99.1% toward catalytic degradation of 4-CP within 30 min under the optimal conditions. Moreover, CFNC-30 NPs demonstrated durability and long-term stability even during the five consecutive cycle tests without a significant drop in its catalytic performance. The scavenging experiments and electron paramagnetic resonance technologies revealed that non-radical singlet oxygen (1O2), sulfate radicals (SO4 −), and hydroxyl radicals (HO ) were involved as active species in the CFNC-30/PMS system, contributing 46.8, 35.6, and 17.6% efficiency toward 4-CP degradation, respectively. Besides, the reaction mechanism on the CFNC-30 NPs and degradation pathways toward 4-CP were speculated under PMS activation. The results indicated that the synergistic effects between zero-valent Co–Fe and N C structures not only significantly boosted the removal efficiency and long-term stability of CFNC-30 NPs, but also facilitated the redox cycles of Co3+/Co2+ and Fe3+/Fe2+. This proof-of-concept approach to develop such high-efficient zero-valent Co–Fe encapsulated in N C structures opens up novel avenues for wastewater decontamination via PMS activation.

Titanate nanotubes (TNTs) were coated with a cyclic oligosaccharide (carboxymethyl-β-cyclodextrin, CM-β-CD) to obtain a photocatalyst (CM-β-CD-TNT) for efficiently activating molecular oxygen and removing the target contaminant. The hydrophobic cavity and the large specific surface area of the photocatalyst provide abundant active sites for activating molecular oxygen. The free radical capture experiment and quenching experiment showed that cyclodextrin could facilitate adsorption and activation of molecular oxygen to produce O

Chloroxylenol (PCMX) is widely used as disinfectant since the epidemic outbreak due to its effective killing of Covid-19 virus. Its stable chemical properties make it frequently detected in surface water. Herein, we successfully modified Fe