Characterisation of aroma compounds, sensory characteristics, and bioactive components of a new type of huangjiu fermented with Chinese wild rice (Zizania latifolia).

Chinese wild rice (CWR) is a nutritious and healthy whole grain, worth developing. To develop and use its value, a new type of huangjiu was brewed with CWR, and the flavour characteristics, sensory quality, functional and bioactive components were evaluated. CWR (67 flavour substances) and glutinous rice (GR)-CWR huangjiu (62 flavour substances) had a better flavour than GR huangjiu (54 flavour substances), and the overall style of GR-CWR huangjiu was more skewed towards GR. The fruity, honey, caramel-like, herb and smoky aroma attributes of CWR huangjiu were higher than those of GR huangjiu (P < 0.05), while only the alcoholic was weaker (P < 0.05) due to the lower alcohol content. The huangjiu brewed using CWR had a better taste than that brewed using only GR. Furthermore, CWR huangjiu had the highest content of total dietary fiber (732.0 ± 15.2 mg/100 g), followed by GR-CWR (307.0 ± 8.5 mg/100 g), and GR (127.0 ± 2.3 mg/100 g). CWR huangjiu also had the highest total phenolic compounds (3.32 ± 0.05 mg/100 g/%vol) and total saponins (2.46 ± 0.03 mg/100 g/%vol) contents, followed by GR-CWR and GR. This study provides guidance for exploring further possibilities for CWR in the future.

Temporal dynamics of genetic architecture governing leaf development in Populus.

Leaf development is a multifaceted and dynamic process orchestrated by a myriad of genes to shape the proper size and morphology. The dynamic genetic network underlying leaf development remains largely unknown. Utilizing a synergistic genetic approach encompassing dynamic genome-wide association study (GWAS), time-ordered gene co-expression network (TO-GCN) analyses and gene manipulation, we explored the temporal genetic architecture and regulatory network governing leaf development in Populus. We identified 42 time-specific and 18 consecutive genes that displayed different patterns of expression at various time points. We then constructed eight TO-GCNs that covered the cell proliferation, transition, and cell expansion stages of leaf development. Integrating GWAS and TO-GCN, we postulated the functions of 27 causative genes for GWAS and identified PtoGRF9 as a key player in leaf development. Genetic manipulation via overexpression and suppression of PtoGRF9 revealed its primary influence on leaf development by modulating cell proliferation. Furthermore, we elucidated that PtoGRF9 governs leaf development by activating PtoHB21 during the cell proliferation stage and attenuating PtoLD during the transition stage. Our study provides insights into the dynamic genetic underpinnings of leaf development and understanding the regulatory mechanism of PtoGRF9 in this dynamic process.

Allelic variations of WAK106-E2Fa-DPb1-UGT74E2 module regulate fibre properties in Populus tomentosa.

Wood formation, intricately linked to the carbohydrate metabolism pathway, underpins the capacity of trees to produce renewable resources and offer vital ecosystem services. Despite their importance, the genetic regulatory mechanisms governing wood fibre properties in woody plants remain enigmatic. In this study, we identified a pivotal module comprising 158 high-priority core genes implicated in wood formation, drawing upon tissue-specific gene expression profiles from 22 Populus samples. Initially, we conducted a module-based association study in a natural population of 435 Populus tomentosa, pinpointing PtoDPb1 as the key gene contributing to wood formation through the carbohydrate metabolic pathway. Overexpressing PtoDPb1 led to a 52.91% surge in cellulose content, a reduction of 14.34% in fibre length, and an increment of 38.21% in fibre width in transgenic poplar. Moreover, by integrating co-expression patterns, RNA-sequencing analysis, and expression quantitative trait nucleotide (eQTN) mapping, we identified a PtoDPb1-mediated genetic module of PtoWAK106-PtoDPb1-PtoE2Fa-PtoUGT74E2 responsible for fibre properties in Populus. Additionally, we discovered the two PtoDPb1 haplotypes that influenced protein interaction efficiency between PtoE2Fa-PtoDPb1 and PtoDPb1-PtoWAK106, respectively. The transcriptional activation activity of the PtoE2Fa-PtoDPb1 haplotype-1 complex on the promoter of PtoUGT74E2 surpassed that of the PtoE2Fa-PtoDPb1 haplotype-2 complex. Taken together, our findings provide novel insights into the regulatory mechanisms of fibre properties in Populus, orchestrated by PtoDPb1, and offer a practical module for expediting genetic breeding in woody plants via molecular design.

Significant roles of surface functional groups and Fe/Co redox reactions on peroxymonosulfate activation by hydrochar-supported cobalt ferrite for simultaneous degradation of monochlorobenzene and p-chloroaniline.

CoFe2O4/hydrochar composites (FeCo@HC) were synthesized via a facile one-step hydrothermal method and utilized to activate peroxymonosulfate (PMS) for simultaneous degradation of monochlorobenzene (MCB) and p-chloroaniline (PCA). Additionally, the effects of humic acid, Cl-, HCO3-, H2PO4-, HPO42- and water matrices were investigated and degradation pathways of MCB and PCA were proposed. The removal efficiencies of MCB and PCA were higher in FeCo@HC140-10/PMS system obtained under hydrothermal temperature of 140 °C than FeCo@HC180-10/PMS and FeCo@HC220-10/PMS systems obtained under higher temperatures. Radical species (i.e., SO4•-, •OH) and nonradical pathways (i.e., 1O2, Fe (IV)/Co (IV) and electron transfer through surface FeCo@HC140-10/PMS* complex) co-occurred in the FeCo@HC140-10/PMS system, while radical and nonradical pathways were dominant in degrading MCB and PCA respectively. The surface functional groups (i.e., C-OH and CO) and Fe/Co redox cycles played crucial roles in the PMS activation. MCB degradation was significantly inhibited in the mixed MCB/PCA solution over that in the single MCB solution, whereas PCA degradation was slightly promoted in the mixed MCB/PCA solution. These findings are significant for the provision of a low-cost and environmentally-benign synthesis of bimetal-hydrochar composites and more detailed understanding of the related mechanisms on PMS activation for simultaneous removal of the mixed contaminants in groundwater.

The derivation of soil generic assessment criteria for polychlorinated biphenyls under the agricultural land scenario in Pearl and Yangtze River Delta regions, China.

The agricultural soils in China are suffered from serious polychlorinated biphenyls (PCBs) contamination, however, the valid management standards for farmland are absent to efficiently control the health risks of PCBs exposure. This study analyzed the contamination characteristics and main composition of PCBs in agricultural soils of the southeastern China from the published literature over the past 20 years, and derived the regional generic assessment criteria (GAC) using an exposure modelling approach for individual and total PCBs (∑PCBs) via multiple exposure pathways such as ingestion of soil and dust, consumption of vegetables, dermal contact with soil and dust, ingestion of soil attached to vegetables, and inhalation of soil vapour and soil-derived dust outdoors under the agricultural land scenario. It is identified that the averaged ∑PCBs concentration of 80.03 ng g-1 under the 95 % lower confidence limit with an unacceptable health risk of 4.8 × 10-6 has significantly exceeded the integrated generic assessment criteria (expressed as GACint) of 16.5 ng g-1. Accordingly, the exposure pathways from the consumption of agricultural produces and indirect ingestion of soil attached to vegetables contributed up to 62 %-88 % of the total exposure, followed by 11 %-33 % of the soil ingestion and 2 %-6 % of dermal contact. The derived GACint for ∑PCBs is extremely valuable to effectively assess and manage the PCBs contamination in agricultural soils of China.

Hong Kong Adolescents' Participation in Political Activities: Correlates of Violent Political Participation.

The present study aimed to examine Hong Kong junior secondary school students' participation in different types of political activities, to identify profiles of adolescents based on their political participation, and to examine potential protective and risk factors associated with adolescents' violent political participation during the social unrest in Hong Kong from a positive youth development perspective. A total of 2,016 students (age = 13.92 ± 1.10 years) recruited from 24 secondary schools in Hong Kong participated in an online survey six months after the social unrest subsided. The findings provide a comprehensive descriptive profile of Hong Kong adolescents' political participation. Four clusters of adolescents with homogeneous patterns of political participation were identified: (1) "Politically Inactive" (42.6%); (2) "Legal Participant" (27.5%); (3) "Radical/Violent Activist" (13.0%); and (4) "Peaceful Activist" (17.0%). Logistic regression analysis showed that being female, born in Hong Kong, having a weak local identity and a strong national identity, a high level of bonding, prosocial involvement and prosocial norms, a low level of parental psychological control and family conflict, and a good parent-child relationship were associated with a low risk of adolescents' violent political participation. The findings point to the needs to further promote social cohesion in Hong Kong society, to help adolescents avoid the potentially essentialized dichotomy in their identity construction, and to develop programs targeting the identified risk and protective factors to prevent adolescents from engaging in political violence and to promote their civic participation.

Effective and simultaneous removal of heavy metals and neutralization of acid mine drainage using an attapulgite-soda residue based adsorbent.

Implementing an economical and effective measure for treating acid mine drainage (AMD) from abandoned mines using low-cost restoration reagents present a significant challenge. In this study, natural attapulgite (AT) and soda residue (SR) composite particles (AT-SR) were firstly prepared and utilized in AMD treatment. The efficiencies and mechanisms of AT-SR composites for regulating acidity and removing metals in AMD, the critical factors influencing the treatment efficiencies, and the regeneration performance and environmental risk were investigated. It is illustrated that AT and SR quality ratio of 5:5, dosage of 0.5 g L-1, particle size < 1.5 mm, concentrations of 150 mg L-1 for Fe, 75 mg L-1 for Mn and 100 mg L-1 for Cu, Zn, Cd and Pb, and adsorption time of 120 min were the optimized conditions. The maximum adsorption capacities of Fe, Mn, Cu, Zn, Cd and Pb under single metal scenarios were 51.61, 22.30, 37.05, 40.21, 37.39 and 49.53 mg g-1, respectively. Under the mixed metal scenarios, competitive adsorption was predominated with the rate constants in the reducing order of 3.169 for Fe > 0.841 for Cu > 0.657 for Pb > 0.083 for Zn > 0.024 for Cd > 0.006 for Mn. The experimental data was fitted well with the pseudo-second-order and the Freundlich isotherm models. AT-SR is an outstanding neutralizer for AMD due to its richness in calcium and magnesium oxides and the spent AT-SR composites could be easily regenerated while maintaining high metal removal efficiencies under the subsequent usages. It is determined under the aqua regia digestion and Toxicity Characteristic Leaching Procedure (TCLP) tests that AT-SR can be used safely without posing environmental risks, thus promoting the resource recovery and utilization of soda residue and providing a green and effective method for treating AMD.

The evolution of stable nanohybrids to complex heteroaggregates between nZVI and soil nanoparticles: The influence of ionic strength and soil components.

The heteroaggregation mechanism of nZVI with four types of natural soil nanoparticles (SNPs) extracted from representative soils in northern and southern China was investigated. Heteroaggregation rates between nZVI and SNPs were quantified by dynamic light scattering and evaluated as a function of ionic strength at pH 7. The nZVI-SNPs heteroaggregates were stable with hydrodynamic diameters (Dh) ranging from 400 to 600 nm in 0.1 mM solution. Based on the extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, nZVI underwent heteroaggregation with SNPs to form stable nZVI-SNPs nanohybrid due to the attachment of nZVI on the SNPs. However, with enhanced ionic strength, SNPs accelerated the aggregation of nZVI and formed large heteroaggregates with Dh in the range from 1200 to 2000 nm, owing to insignificant electrostatic repulsions and oppositely charged patches. In addition, the differences in the heteroaggregation rates of nZVI with four SNPs were negligible, caused by the negligible impacts of SNPs components such as soil organic matter and Fe/Al oxyhydroxides on the heteroaggregation of nZVI in the 10 mM NaCl solution. These findings are helpful for understanding the interaction between nZVI and SNPs and of significance to groundwater remediation using nZVI.

Hydrothermally assisted synthesis of nano zero-valent iron encapsulated in biomass-derived carbon for peroxymonosulfate activation: The performance and mechanisms for efficient degradation of monochlorobenzene.

A facile, green and easily-scalable method of synthesizing stable and effective nano zero-valent iron (nZVI)­carbon composites for peroxymonosulfate (PMS) activation was highly desirable for in-situ groundwater remediation. This study developed a two-step hydrothermally assisted carbothermal reduction method to prepare nZVI-encapsulated carbon composite (Fe@C) using rice straw and ferric nitrate as precursors. The hydrothermal reactions were conducive to iron loading, and carbothermal temperature was crucial for the aromatization and graphitization of hydrothermal carbonaceous products, the reductive transformation of iron oxides into nZVI and the development of porous structure in composites. At carbothermal temperature of 800 °C following hydrothermal reactions, the stable Fe@C800 with nZVI encapsulated in the spherical carbon shell was obtained and exhibited the best catalytic performance for PMS activation and the degradation of monochlorobenzene (MCB) in a wide range of pH values (3-11) with removal efficiency after 120 min reaction and first-order kinetic rate constant (k1) of 98.7% and 0.087 min-1 respectively under the optimum conditions of 10 mM PMS and 0.2 g·L-1 Fe@C800. The inhibiting effects of common co-existed anions (i.e., Cl-, HCO3- and H2PO4-) and humic acid in groundwater on the removal of MCB in Fe@C800/PMS system was also investigated. Both OH-dominated radical processes and nonradical pathways involving 1O2 and surface electron transfers were accounted for PMS activation and MCB removal. The inner nZVI was protected by the carbon shell, endowing Fe@C800 with high reactivity and good reusability. Additionally, 81.2% and 73.5% of MCB removal rates were achieved in tap water and actual contaminated groundwater respectively. This study not only provided a novel strategy to synthesize highly effective and stable nZVI­carbon composites using the agricultural biomass waste for PMS induced oxidation of organic contaminants in groundwater, but also enhanced the understanding on the activation mechanism of iron­carbon based catalysts towards PMS.

An investigation of citizenship construction among students in higher education: a Foucauldian perspective.

This study, adopting the Foucauldian lenses of citizenship, investigates how a group of students understand the prevailing social discourses and how such understanding and perceptions influence students' sense of citizenship and coping strategies. Drawing on in-depth individual interviews with 28 participants from six universities in Hong Kong, the findings suggest that multiple factors have impacts on the university students' sense of citizenship, including the media as technologies to shape citizenship, the essentialized ideological differences as an apparatus of intervention to shape and act upon individuals, and the legitimacy and discordance of opinions among individuals within both physical and virtual communities. The participants were found to gradually develop an awareness of the discursive construction of the social. They were found to search for their sense of citizenship through (a) opting for one ideological stance and/or keeping silent to avoid being othered within the social discourses existing at the social, community, and family levels; (b) adopting different coping strategies when dealing with their confusion towards conflicting comments; or (c) developing news reading literacy and coming to the realization of the role media plays in discursively constructing new citizens and exercising influence over existing and potential members of communities. The implications of the findings for curriculum design and policy making to develop support measures to facilitate students' positive learning and whole-person development are discussed.

Carbon stability and mobility of ball milled lignin- and cellulose-rich biochar colloids.

Numerous studies have explored the transport mechanism of biochar colloids in porous medium. However, the effect of feedstock biopolymer compositions and pyrolytic temperature on carbon stability and mobility of biochar colloids is limited. This study prepared four ball milled biochar colloids pyrolyzed from lignin-rich pinewoods and cellulose-rich corn stalks under 300 °C and 500 °C (termed as PW300, PW500, CS300, CS500) and analyzed their differences in the chemical stability and transport behaviors. The results indicated that high contents of lignin in biomass and pyrolytic temperature could enhance the compact aromatic structures of biochar colloids characterized by the elemental composition, FTIR, 13C NMR and XRD analyses. Therefore, PW500 with the strongest chemical stabilities (least C loss of 13%), electronegativity (-44.9 mV vs. -41.6-28.3 mV) and smallest hydrodynamic diameter (608.7 nm vs. 622-997.2 nm) was obtained under ball milling. Moreover, both the critical coagulation concentrations (CCC) and the maximum relative effluent concentration (C/C0) with the NaCl ionic strength of 1 mM were demonstrated to be in the increase order of CS300 (76.1 mM, 70%) < PW300 (183.1 mM, 78%) < CS500 (363.9 mM, 89%) < PW500 (563.1 mM, 95%), which suggested stronger colloidal stability and mobility of PW biochar colloids than those of CS biochar colloids. In addition, the C/C0 for CS300, PW300 and CS500 were about 7.3%-36% lower than that for PW500 with the NaCl ionic strength increasing to 50 mM indicated the notable superiority in the mobility of PW500. These findings can provide new insights toward understanding the transformation and migration, and evaluating the environmental risk of biochar colloids.

Degradation of 1,4-dioxane by biochar activating peroxymonosulfate under continuous flow conditions.

1,4-Dioxane degradation under both batch-scale and column experiments has been investigated within the biochar activated peroxymonosulfate (PMS) system for in-situ remediation of 1,4-dioxane contaminated groundwater. In case of the batch experiments, the 1,4-dioxane degradation efficiencies were significantly increased with the increased biochar pyrolysis temperatures. The optimized 1,4-dioxane degradation efficiency at 89.2% was achieved with 1.0 g L-1 of biochar (E800) and 8.0 mM PMS. In the absence of PMS, the breakthrough rates of 1,4-dioxane in biochar packed column experiments under the dynamic flow conditions were relatively slow compared with those in sand packed columns. Simultaneously, based on the integrated areas (IA) from the 1,4-dioxane breakthrough curves, the degradation efficiency at 70.2% was estimated in biochar packed column (WE800:WSand = 1:9) under continuous injections of 16.0 mM PMS. Electron paramagnetic resonance (EPR) indicated that hydroxyl, sulfate and superoxide radicals were generated within the biochar/PMS systems and alcohol quenching experiments suggested that the dominated hydroxyl and sulfate radicals were responsible for 1,4-dioxane degradation. The findings of this study suggested that the biochar activated PMS system is a promising and cost-effective strategy for the remediation of 1,4-dioxane contaminated groundwater.

Structural insights revealed by crystal structures of CYP76AH1 and CYP76AH1 in complex with its natural substrate.

CYP76AH1 is the key enzyme in the biosynthesis pathway of tanshinones in Salvia miltiorrhiza, which are famous natural products with activities against various heart diseases and others. CYP76AH1 is a membrane-associated typical plant class II cytochrome P450 enzyme and its catalytic mechanism has not to be clearly elucidated. Structural determination of eukaryotic P450 enzymes is extremely challenging. Recently, we solved the crystal structures of CYP76AH1 and CYP76AH1 in complex with its natural substrate miltiradiene. The structure of CYP76AH1 complexed with miltiradiene is the first plant cytochrome P450 structure in complex with natural substrate. The studies revealed a unique array pattern of amino acid residues, which may play an important role in orienting and stabilizing the substrate for catalysis. This work would provide structural insights into CYP76AH1 and related P450s and the basis to efficiently improve tanshinone production by synthetic biology techniques.

Trichloroethylene dechlorination rates, pathways, and efficiencies of ZVMg/C in aqueous solution.

The removal mechanism from the reductive dechlorination of trichloroethylene (TCE) by zero valent magnesium (ZVMg) in aqueous solution is systematically studied. Following the preparation and characterization of ball-milled micro ZVMg with graphite (ZVMg/C) particles, this paper evaluated the TCE reaction rates, pathways, utilization rates and aging effects of ZVMg/C particles in aqueous solution under uncontrolled pH conditions. Overall, 38 µM of TCE was transformed by 10 g/L of ZVMg/C to methane (62.51%) and n-hexane (11.86%) and ethane (7.40%) and other alkene and alkyne products through the catalytic hydrogenation pathway. The measured surface area normalized pseudo-first order rate constants (KSA) were up to 9.31 × 10-2 L/m2/h and the utilization rate of Mg0 accounted for around 60%. The KSA were decreased to 1.90 × 10-2 L/m2/h in case of ZVMg/C being exposed in the atmosphere for 6 days due to 7.3% reduction in the utilization rate of Mg0 from the initial 85.2%, and 5.11 × 10-2 L/m2 h in case of ZVMg/C aged in water for one day. The removal efficiencies of approximately 56%, 58% and 87% by 10 g/L of ZVMg/C were achieved in the contaminated groundwater comprising 38 µM of TCE, 43 µM of 1,2-dichlorobenzene and 8.12 µM of trichlormethane. Therefore, it is concluded that ZVMg/C is viewed as a potential and effective remediation reagent for the groundwater remediation.

Effects of multiple injections on the transport of CMC-nZVI in saturated sand columns.

The multiple injections of nanoscale zero valent iron (nZVI) slurry, an efficient method to remediate contaminated groundwater, requires an accurate assessment of the transport and risks of these particles in saturated porous medium. However, the influencing mechanism of nZVI transport under multiple injection conditions is not fully understood. In this experimental study, one-dimensional sand columns were used to evaluate the effects of injection concentrations, particle sizes and surface chemical corrosion on the transport of carboxymethyl cellulose modified nZVI (CMC-nZVI) under triple injection conditions, where the different volumes of NaCl solution were flushed through the columns between the injections. Based on the breakthrough curves and retention profiles under flushing 4 pore volumes of NaCl solution between the injections, the transport of CMC-nZVI particles was gradually enhanced attributable to the exclusion among these particles at injection concentration of 200 mg/L, but the opposite was observed due to large aggregation caused by strong magnetic force among particles at 500 mg/L. However, the magnitudes of enhancement or reduction on maximum C/C0 under the above injection concentrations were related to the smallest particle size of Dh = 3.926 µm because of high particle number concentrations leading to intense competition on depositional sites at 200 mg/L and significant aggregation at 500 mg/L. Conversely, the transport of CMC-nZVI was reduced under flushing 76 pore volumes of NaCl solution between the injections because of pronounced corrosion of CMC-nZVI in water as evidenced by the XPS and XRD analyses of particles. This corrosion could cause the decrease in repulsion among particles due to the increase in surface negative zeta potential and the CMC desorption from nZVI. Accordingly, this study revealed that relative high injection concentrations and chemical corrosion in groundwater could restrain the mobility of nZVI under multiple injection conditions and the potential risks posed by CMC-nZVI are controllable.

Nanoscale zero-valent iron supported by attapulgite produced at different acid modification: Synthesis mechanism and the role of silicon on Cr(VI) removal.

The attapulgite of different morphologies and mineral compositions were successfully obtained following the treatment by HCl and HF with different concentrations. Variations of morphologies, elemental and mineral components of the pristine and modified attapulgite were investigated and assessed in detail by a series of characterization methods. The SEM-EDS results indicated significant variations on the contents and morphologies of silicon after acid modification. The Cr(VI) removal efficiencies under pristine and modified attapulgite-supported nZVI composites were evaluated with the removal rate in case of 0.5HAT-nZVI being 69.2% more superior than that of 6FAT-nZVI. The reaction kinetic is well fitted with pseudo second order kinetics model. The correlation analysis indicated that Cr(VI) removal efficiency was positively correlated with the content of active silicon in the attapulgite-nZVI composites (R2 = 0.979∗∗). Additionally, the reduction of Cr(VI) is more likely to occur in silicon-rich composites based on the analysis of XPS spectra and Cr concentration changes, which were mainly attributed to the enhanced Si-O-Fe coupling mediated by silicon. Attapulgite with more exposure sites of silicon enhanced the Cr(VI) reduction process and promoted crystallization of the reaction products. Simultaneously, the nZVI consumption caused by oxidation and aggregation were improved by silicon in attapulgite. It is concluded that silicon played a significant role on Cr(VI) removal through the reductive precipitation by Si-O-Fe coupling.

Mechanistic insights into fast adsorption of perfluoroalkyl substances on carbonate-layered double hydroxides.

Layered double hydroxide (LDH) with the metal composition of Cu(II)Mg(II)Fe(III) was prepared as an adsorbent for fast adsorption of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA). 84% of PFOS and 48% of PFOA in relation to the equilibrium state were adsorbed in the first minutes of contact with 0.1 g/L of suspended µm-sized LDH particles. The adsorption mechanisms of PFOS and PFOA on the CuMgFe-LDH were interpreted. Hydrophobic interactions were primarily responsible for the adsorption of these compounds in accordance with the different adsorption affinities of long-chain (C8, Kd = 105 L/kg) and short-chain (C4, Kd = 102 L/kg) perfluorinated carboxylic acids. PFOA adsorption on CuMgFe-LDH was strongly suppressed under alkaline conditions while PFOS uptake was only slightly affected in the pH range from 4.3 to 10.7, indicating a significant role of electrostatic interactions for PFOA adsorption. The adsorption of PFOS and PFOA was rather insensitive to competition by monovalent anions. The previously reported 'memory effect' of calcined CuMgFe-LDH for sorption of organic anions was not confirmed in the present study. Spent CuMgFe-LDH could be easily regenerated by extraction with 50 vol% methanol in water within 1 h and maintained a high PFOS removal in subsequent usage cycles.

Effects of feedstock biopolymer compositions on the physiochemical characteristics of dissolved black carbon from lignocellulose-based biochar.

Dissolved black carbon (DBC) is becoming increasingly concerned by researchers due to its unique environmental behavior. However, understanding of the influence mechanism of biopolymer compositions of cellulose (CEL), hemicellulose (HEM) and lignin (LIG) on the formation and physiochemical characteristics of DBC from lignocellulose-based biochar is limited. This study therefore examined the formation of DBCs derived from the biopolymer compositions, corn straw (CS), corncob (CC), bamboo sawdust (BS) and pinewood sawdust (PS) under the heat treatment temperatures (HTTs) of 300-500 °C. Zeta potential and hydrodynamic diameters (Dh) of DBCs produced under 300 °C were further investigated. DBC formation may be closely associated with the HTT-dependent heterogeneities of biopolymer compositions, in which significant effects of CEL and HEM charring on physiochemical properties of DBCs were identified under the HTT of 300 and 400 °C, while the formation of DBCs was closely related to LIG and its proportions in biomass under high HTT (>500 °C). On the rise of the HTT, the carbonaceous structures of biopolymer compositions were reorganized and converted to graphitic structures in biochar accompanied by the large decomposition or carbonization of CEL and HEM, leading to the reduced carbon content, surface functional groups, aromaticity and molecular weight of DBCs, as well as the decrease of protein-like and relative increase of fulvic-like fluorescent substances in most DBCs. LIG in biomass may facilitate the migration of DBCs due to abundant surface negative charges and the formation of low Dh. This study offered new insights into our understanding of influencing mechanisms of biopolymer compositions on the characteristic of DBCs under different HTTs.

Enhanced removal of 1,2,4-trichlorobenzene by modified biochar supported nanoscale zero-valent iron and palladium.

Biochar pyrolysed at 300 °C, 500 °C, 700 °C was modified by hydrochloric acid (HCl), hydrofluoric acid (HF), sodium hydroxide (NaOH), hydrogen peroxide (H2O2), nitric acid (HNO3) and potassium permanganate (KMnO4), and subsequently evaluated for removal efficiency of 1,2,4-trichlorobenzene (1,2,4-TCB) by biochar supported nanoscale zero-valent iron (nZVI) and palladium (Pd) composites. Under the initial 1,2,4-TCB concentration of 10 mg L-1 and the solid-liquid ratio of 0.16 g L-1, the synthesized composites of nZVI-Pd with BC700 modified by HF (FBC700-nZVI-Pd) and nZVI-Pd with BC300 modified by NaOH (SBC300-nZVI-Pd) demonstrated significantly enhanced removal efficiencies for 1,2,4-TCB achieving 98.8% and 94.7% after 48 h, respectively. The physicochemical properties of biochar including specific surface area, aromaticity and hydrophobicity after the modification by HF and NaOH were improved. Increased the supporting sites for Fe/Pd nanoparticles and the contact between composites and 1,2,4-TCB were mainly responsible for enhanced removal efficiency for 1,2,4-TCB. Both the adsorption by biochar and reduction by Fe/Pd nanoparticles effectively contributed to the removal of 1,2,4-TCB. It is estimated that the proportion of reduction was about twice that of adsorption in the first 12 h, which produced 1,2-DCB, benzene and other degradation products. Therefore, biochar treated with HF and NaOH and supported Fe/Pd nanoparticles could be effective functional materials for remediation of groundwater contaminated by 1,2,4-TCB.

Crystal structure of CYP76AH1 in 4-PI-bound state from Salvia miltiorrhiza.

Tanshinones are important diterpenoid secondary metabolites from Salvia miltiorrhiza, widely used as cardiovascular and cerebrovascular medicines. CYP76AH1 is a membrane-associated cytochrome P450 enzyme and plays a critical role in the biosynthetic pathway of tanshinones. To clarify the relationship between structure and function of CYP76AH1, we recently constructed the expression vector of CYP76AH1 and purified the enzyme. The engineered CYP76AH1 was expressed in E. coli Trans-blue cells and exhibited enhanced expression and solubility. The proper folding of the engineered CYP76AH1 was assessed by CO difference spectrum assay. Functional identification of the recombinant enzyme was performed by conducting enzymatic reaction with the purified CYP76AH1 in presence of substrate, the co-factor NADPH and the purified SmCPR1 (cytochrome P450 reductase from Salvia miltiorrhiza), and by subsequently analyzing the reaction extract through GC-MS. X-ray crystal complex structure of CYP76AH1 with inhibitor 4-phenylimmidazole (4-PI) was determined at the resolution of 2.6 Å. In the ligand-binding cavity of 4-PI bound CYP76AH1, the inhibitor 4-PI forms a hydrogen bound with a water molecule which coordinates with heme at the sixth coordination position. There are two open channels which substrate and product site may access and leave the active site. In the CYP76AH1/4-PI complex structure, the imidazole ring of 4-PI is parallel to helix I instead of perpendicular to helies I in most P450s bound imidazole. 4-PI may be work in the stability of CYP76AH1 crystal structure. These studies provide information on functional expression and purification of CYP76AH1, and overall structure of CYP76AH1 complexed with 4-PI.