Photocatalysis is an effective technology for NO removal even at low concentrations in the ambient atmosphere. However, the low efficiency of this advanced process and the tendency of producing toxic ...byproducts hinder the practical application of photocatalysis. To overcome these problems, the Bi@Ba2TiO4/BaBi4Ti4O15 photocatalytic composites were successfully prepared by a one-step hydrothermal method. The as-synthesized photocatalysts exhibited an efficient photocatalytic performance and generated low amounts of toxic byproducts. X-ray diffraction studies show that Bi3+ is successfully reduced on the surface of Ba2TiO4/BaBi4Ti4O15 (BT/BBT). After L-Ascorbic acid (AA) modification, the photocatalytic NO removal efficiency of Bi@Ba2TiO4/BaBi4Ti4O15 is increased from 25.55% to 67.88%, while the production of the toxic byproduct NO2 is reduced by 92.02%, where the initial concentration of NO is diluted to ca. 800 ppb by the gas stream and the flow rate is controlled at 301.98 mL·min−1 in a 150 mL cylindrical reactor. Furthermore, ambient humidity has little effect on the photocatalytic performance of theBi@Ba2TiO4/BaBi4Ti4O15, and the photocatalyst exhibits excellent reusability after repeated cleaning with deionized water. The improved photocatalytic effect is attributed to the addition of AA in BT/BBT being able to reduce Bi3+ ions to form Bi nanoparticles giving surface plasmon effect (SPR) and generate oxygen vacancies (OVs) at the same time, thereby improving the separation efficiency of photogenerated carriers, enhancing the light absorption, and increasing the specific surface areas. The present work could provide new insights into the design of high-performance photocatalysts and their potential applications in air purification, especially for NO removal.
A series of biopolymer based complex were manufactured by coordinating iron ions to the abundant amino- and sulfur-containing groups in the modified wool and used as heterogeneous Fenton-like ...photocatalyst for 4-chlorophenol（4-CP） degradation in the presence of H2O2.Hydroxylamine hydrochloride（NH2OH·HC1） or acrylic acid was employed to modify the natural wool to strengthen the interaction with iron and to reinforce the structural stability.The NH2OH·HC1 modified wool based complex showed the best catalytic performance for 4-CP degradation.The strong coordination between iron and great number of hydroxamic acid in this modified complex leads to the least iron leaching during the tests.HO· species was confirmed to be the dominant reactive oxidant in the decontamination process.The approach presented in this study can provide a new approach for developing novel bioployermer-based photocatalysts for efficient degradation of toxic organic pollutants such as 4-CP.
•Recent advances in non-centrosymmetric (NCS) photocatalytic materials are reviewed.•Intrinsic polarization and its role in photocatalysis are throughly illustrated.•Polarization and relevant ...physical properties are profoundly collrelated.•Strategies towards improving polarization are systematically reviewed.•Challenges and prospects of NCS photocatalytic materials are discussed.
The conversion of solar energy into chemical energy through semiconductor-based photocatalysis technology is an appealing strategy towards resolving the energy crisis and environmental pollution issues. However, the practical application of photocatalysis is impeded by its limited photocatalytic efficiency due to the intrinsic nature of photocatalysts, i.e., recombination of photogenerated electrons and holes. To this end, non-centrosymmetric (NCS) based photocatalytic materials including piezoelectrics, pyroelectrics, ferroelectrics and nonlinear optical (NLO) materials are attractive, which can not only convert mechanical energy and temperature fluctuation in the environment besides solar energy into secondary energy, but can also promote the separation of photogenerated charge carriers due to their built-in electric field resultant polarization, thus greatly improving their photocatalytic performance. Here, we first surveyed the recent advances in of NCS-based photocatalytic materials. Further, the correlation of their polarization-related physical properties with their photocatalytic activities and the strategies towards improving polarization of NCS materials were systematically summarized and highlighted, aiming to clarify the correlation of the improvement of polarization with the enhanced photocatalytic performance. Subsequently, the photocatalytic mechanism and multiple applications of photocatalysis in environmental remediation and energy conversion based on NCS materials were presented. Meanwhile, we discussed the remaining challenges for NCS materials and strategies for enhancing their photocatalytic efficiency. Finally, the development trend and future perspectives of NCS photocatalytic materials in environmental chemical engineering is presented.
This review is intended to evaluate the use of ferrate (Fe(VI)), being a green coagulant, sustainable and reactive oxidant, to remove micro pollutants especially pharmaceutical pollutants in ...contaminated water. After a brief description of advanced oxidation processes, fundamental dimensions regarding the nature, reactivity, and chemistry of this oxidant are summarized. The degradation of contaminants by Fe(VI) involves several mechanisms and reactive agents which are critically evaluated. The efficiency and chemistry of Fe(VI) oxidation differs according to the reaction conditions and activation agent, such as soluble Fe(VI) processes, which involve Fe(VI), UV light, and electro-Fe(VI) oxidation. Fe(VI) application methods (including single dose, multiple doses, chitosan coating etc), and Fe(VI) with activating agents (including sulfite, thiosulfate, and UV) are also described to degrade the micro pollutants. Besides, application of Fe(VI) to remove pharmaceuticals in wastewater are intensely studied. Electrochemical prepared Fe(VI) has more wide application than wet oxidation method. Meanwhile, we elaborated Fe(VI) performance, limitations, and proposed innovative aspects to improve its stability, such as the generation of Fe(III), synergetic effects, nanopores entrapment, and nanopores capsules. This study provides conclusive direction for synergetic oxidative technique to degrade the micro pollutants.
Display omitted
•Recent advancements in ferrate's (Fe(VI)) remediation to degrade micro pollutants.•Potential reactive agents to facilitate Fe(V)/Fe(IV) for more redox potential than Fe(VI).•The degradation of micro pollutant is mediated by catalytic activities.•Activation of Fe(VI) by UV was systematically reviewed.
Display omitted
•Both SAS and CTAC maintain moisture in the composting process.•Surfactants accelerate the degradation of organic matter.•Firmicutes and Proteobacteria were more abundant in SAS and ...CTAC than in CK.•Amino acid and carbohydrate metabolism are the main metabolic pathways.
The purpose of this study was to investigate the effects of anionic and cationic surfactants on the physico-chemical properties, organic matter (OM) degradation, bacterial community structure and metabolic function during composting of dairy manure and sugarcane bagasse. The results showed that the surfactant could optimize the composting conditions to promote the degradation of OM. The most OM degradation and humic substances (HS) synthesis were observed in SAS. Firmicutes and Proteobacteria were more abundant in SAS and CTAC, and Actinobacteria in CK. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) showed that SAS and CTAC are more abundant than CK in genes related to metabolism, environmental and genetic information processing. The correlation analysis showed that the dominant bacteria had more significant correlation with environmental factors. In general, the anionic surfactant could better promote the degradation of OM, change the structure of microbial community, and improve the quality of compost.
The aim of this study was to investigate the impacts of red mud on lignin degradation, humic substance formation and laccase-producing bacterial community in composting to better improve composting ...performances. The results indicated that the organic matter contents of final compost products in the treatment group with red mud (T) decreased by 25.74%, which was more than the control group without red mud (CK) (12.09%). The final lignin degradation ratio and humic substance concentration of the T were 18.67% and 22.80% higher than that of the CK, respectively. The final C/N values of compost in the CK and T were 11.32 and 10.66, respectively, which were both less than 15, suggesting that compost reached maturity. Redundancy analysis showed that temperature was the main factors driving the variation of laccase-producing bacterial community. Pearson analysis suggested that Pseudomonas, Phenylobacterium, and Caulobacter were the most significantly correlated with lignin degradation and humification in the T.
Display omitted
•The decomposition of organic matter was accelerated by adding red mud.•Red mud promoted lignin degradation and HS formation during composting.•Red mud additive affected the succession of laccase-producing microbial community.•Proteobacteria was a crucial bacterial phylum secreting laccase.•Temperature was a main factor driving the variation of microbial community.
Display omitted
•Adding SM or NC promoted the transformation of OM and DOM.•NC amendment increased the abundance of cbbL gene based on qPCR analysis.•Both SM and NC improved the diversity of CCAM ...community.•CCAM growth was positively correlated with C/N, TN, pH, OM and DOM via db-RDA and Pearson analysis.
The main purpose of this study was to analyze the effects of different carbon source (Na2CO3, NC; sugarcane molasses, SM) additives on dissolved organic matter (DOM), cbbL-containing autotrophic microbes (CCAM), and the relationship among physico-chemical parameters, DOM and CCAM to better understand carbon transformation in composting. The results showed that SM or NC additive could promote the degradation and transformation of OM and DOM. After adding SM or NC, the Simpson index decreased by 2.03% and 0.51%, respectively, and Luteimonas and Thermomonspora were detected using high throughput sequencing, indicating that SM and NC increased the diversity of CCAM community. Additionally, both NC and SM contributed to improve the abundance of cbbL gene (45.91% and 2.15%) based on fluorescence quantitative PCR (qPCR) analysis at the cooling phase of composting. Pearson correlation analysis revealed that Proteoobacteria, Firmicutes, Acidobacteria and Nematoda were positively related with C/N, OM and DOM (0.5 < R < 0.9, P < 0.05).
Display omitted
•A better performance was shown in pig manure/bagasse pith composting.•More abundant carbohydrate-active enzymes in bagasse pith compost were observed.•A synergistical mechanism of ...lignocellulose degradation was revealed.•Antibiotics and antibiotic resistance genes decreased significantly after composting.
In this study, the differences on the physico-chemical parameters, lignocellulose degradation, dynamic succession of microbial community, gene expression of carbohydrate-active enzymes and antibiotics resistance genes were compared during composting systems of bagasse pith/pig manure (BP) and manioc waste/pig manure (MW). The results revealed that biodegradation rates of organic matter, cellulose, hemicellulose and lignin (29.14%, 17.53%,45.36% and 36.48%) in BP were higher than those (15.59%, 16.74%, 41.23% and 29.77%) in MW. In addition, the relative abundance of Bacillus, Luteimonas, Clostridium, Pseudomonas, Streptomyces and expression of genes encoding carbohydrate- active enzymes in BP were higher than those in MW based on metagenomics sequencing. During composting, antibiotics and antibiotic resistance genes were substantially reduced, but the removal efficiency was divergent in the both samples. Taken together, metagenomics analysis was a potential method for evaluating lignocellulose's biodegradation process and determining the elimination of antibiotic and antibiotic resistance genes from different composting sources of biomass.
In this study, fresh dairy manure and bagasse pith were used as raw materials to study the effect of potassium persulfate in the aerobic composting process. The influence of sulfate radical anion ...(SO4−·) generated by thermally activated persulfate on physicochemical parameters, lignocellulose degradation, humic substance (HS) formation, microbial community succession, and carbohydrate-active enzymes (CAZymes) composition were assessed during composting. Experimental results showed that the degradation rates of cellulose, hemicellulose and lignin in the treatment group with potassium persulfate (PS) (61.47%, 74.63%, 73.1%) were higher than that in blank control group (CK) (59.98%, 71.47%, 70.89%), respectively. Additionally, persulfate additive promoted dynamic variation of dissolved organic matter (DOM) and accelerated the formation of HS. Furthermore, metagenomics analysis revealed that persulfate changed the structure of the microbial community, and the relative abundances of Actinobacteria and Proteobacteria increased by 17.64% and 34.09% in PS, whereas 12.09% and 29.96% in CK. Glycoside hydrolases (GHs) and auxiliary activities (AAs) families were crucial to degrade lignocellulose, and their abundances were more in PS. Redundancy analysis (RDA) manifested that Actinobacteria and Proteobacteria were closely associated with lignocellulosic degradation. In brief, persulfate could accelerate the degradation of organic components, promote the formation of HS, optimize the structure of microbial community, and improve the compost quality.
Display omitted
•Self-generating heat during composting could activate persulfate to produce SO4−·.•SO4−· could accelerate the degradation of lignocellulose.•Actinobacteria and Proteobacteria were vital for lignocellulosic degradation.•GHs and AAs gene abundances were higher in PS than in CK by metagenomics analysis.
PDF
