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1.
J Environ Sci (China) ; 106: 83-96, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34210442

RESUMO

In this work, we employed waste activated sludge (WAS) as carbon source to prepare ultrahigh specific surface area (SSA) biopolymers-based carbons (BBCs) through alkali (KOH) treatment coupled to pyrolysis strategy. Before the pyrolysis process, the involvement of KOH made a great recovery of soluble biopolymers from WAS, resulting in highly-efficient catalytic pyrolysis. The Brunner-Emmett-Teller and pore volume of BBCs prepared at 800°C (BBC800) reached the maximum at 2633.89 m2·g-1 and 2.919 m3·g-1, respectively. X-ray photoelectron spectroscopy suggested that aromatic carbon in the form of C=C was the dominant fraction of C element in BBCs. The N element in BBCs were composed of pyrrolic nitrogen and pyridinic nitrogen at 700°C, while a new graphitic nitrogen appeared over 800°C. As a refractory pollutant of wastewater treatment plants, tetracycline (TC) was selected to evaluate adsorption performance of BBCs. The adsorption behavior of BBCs towards TC was conformed to the pseudo-second-order kinetic and the Langmuir models, signifying that chemisorption of monolayers was dominant in TC adsorption. The adsorption capacity of BBC800 reached the maximum at 877.19 mg·g-1 for 90 min at 298 K. Thermodynamic analysis indicated that the adsorption process was endothermic and spontaneous. Hydrogen bonding and π-π stacking interaction were mainly responsible for TC adsorption, and interfacial diffusion was the main rate-control step in adsorption process. The presence of soluble microbial products (SMPs) enhanced TC removal. This work provided a novel strategy to prepare bio-carbon with ultrahigh SSA using WAS for highly-efficient removal of organic pollutants.


Assuntos
Esgotos , Poluentes Químicos da Água , Adsorção , Álcalis , Biopolímeros , Carbono , Carvão Vegetal , Cinética , Pirólise , Poluentes Químicos da Água/análise
2.
Int J Mol Sci ; 22(11)2021 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-34071909

RESUMO

Corneal transparency relies on the precise arrangement and orientation of collagen fibrils, made of mostly Type I and V collagen fibrils and proteoglycans (PGs). PGs are essential for correct collagen fibrillogenesis and maintaining corneal homeostasis. We investigated the spatial and temporal distribution of glycosaminoglycans (GAGs) and PGs after a chemical injury. The chemical composition of chondroitin sulfate (CS)/dermatan sulfate (DS) and heparan sulfate (HS) were characterized in mouse corneas 5 and 14 days after alkali burn (AB), and compared to uninjured corneas. The expression profile and corneal distribution of CS/DSPGs and keratan sulfate (KS) PGs were also analyzed. We found a significant overall increase in CS after AB, with an increase in sulfated forms of CS and a decrease in lesser sulfated forms of CS. Expression of the CSPGs biglycan and versican was increased after AB, while decorin expression was decreased. We also found an increase in KS expression 14 days after AB, with an increase in lumican and mimecan expression, and a decrease in keratocan expression. No significant changes in HS composition were noted after AB. Taken together, our study reveals significant changes in the composition of the extracellular matrix following a corneal chemical injury.


Assuntos
Queimaduras Químicas/metabolismo , Doenças da Córnea/induzido quimicamente , Doenças da Córnea/metabolismo , Matriz Extracelular/metabolismo , Queimaduras Oculares/induzido quimicamente , Queimaduras Oculares/metabolismo , Álcalis/efeitos adversos , Animais , Biomarcadores , Queimaduras Químicas/diagnóstico , Doenças da Córnea/diagnóstico , Dermatan Sulfato/metabolismo , Modelos Animais de Doenças , Queimaduras Oculares/diagnóstico , Imunofluorescência , Expressão Gênica , Glicosaminoglicanos/metabolismo , Heparitina Sulfato/metabolismo , Sulfato de Ceratano/metabolismo , Camundongos , Proteoglicanas/metabolismo
3.
Environ Sci Technol ; 55(13): 9276-9284, 2021 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-34142799

RESUMO

The deactivation issue arising from alkali poisoning over catalysts is still a challenge for the selective catalytic reduction of NOx by NH3. Herein, improved NOx reduction in the presence of alkaline metals over phosphate-modified Fe2O3/TiO2 catalysts has been originally demonstrated via tailoring the reaction paths by in situ creating alkali-poisoning sites. The introduction of phosphate results in the partial formation of iron phosphate species and makes the catalyst to mainly exhibit the characteristics of FePO4, which is responsible for the widened temperature window and enhanced alkali resistance. The tetrahedral [FeO4]/[PO4] structures in iron phosphate act as the Brønsted acid sites to increase the catalyst surface acidity. In addition, the formation of an Fe-O-P structure enhances the redox ability and increases surface adsorbed oxygen. Furthermore, the created phosphate groups (PO43-) serving as alkali-poisoning sites preferentially combine with potassium so that iron species on the active sites are protected. Therefore, the enhanced NH3 species adsorption capacity, improved redox ability, and active nitrate species remaining in the phosphate-modified Fe2O3/TiO2 catalyst ensure the de-NOx activity after being poisoned by alkali metals through the Langmuir-Hinshelwood reaction pathway. Hopefully, this novel strategy could provide an inspiration to design novel catalysts to control NOx emission with extraordinary resistance to alkaline metals.


Assuntos
Amônia , Fosfatos , Álcalis , Catálise , Titânio
4.
Molecules ; 26(10)2021 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-34067627

RESUMO

Biomineralization, a well-known natural phenomenon associated with various microbial species, is being studied to protect and strengthen building materials such as concrete. We characterized Rhodococcus erythreus S26, a novel urease-producing bacterium exhibiting CaCO3-forming activity, and investigated its ability in repairing concrete cracks for the development of environment-friendly sealants. Strain S26 grown in solid medium formed spherical and polygonal CaCO3 crystals. The S26 cells grown in a urea-containing liquid medium caused culture fluid alkalinization and increased CaCO3 levels, indicating that ureolysis was responsible for CaCO3 formation. Urease activity and CaCO3 formation increased with incubation time, reaching a maximum of 2054 U/min/mL and 3.83 g/L, respectively, at day four. The maximum CaCO3 formation was achieved when calcium lactate was used as the calcium source, followed by calcium gluconate. Although cell growth was observed after the induction period at pH 10.5, strain S26 could grow at a wide range of pH 4-10.5, showing its high alkali tolerance. FESEM showed rhombohedral crystals of 20-60 µm in size. EDX analysis indicated the presence of calcium, carbon, and oxygen in the crystals. XRD confirmed these crystals as CaCO3 containing calcite and vaterite. Furthermore, R. erythreus S26 successfully repaired the artificially induced large cracks of 0.4-0.6 mm width.


Assuntos
Carbonato de Cálcio/metabolismo , Materiais de Construção/microbiologia , Rhodococcus/metabolismo , Álcalis , Biomineralização/fisiologia , Carbonato de Cálcio/química , Precipitação Química
5.
Molecules ; 26(10)2021 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-34069989

RESUMO

Black, brown, and light peat and sapropel were analyzed as natural sources of organic and humic substances. These specific substances are applicable in industry, agriculture, the environment, and biomedicine with well-known and novel approaches. Analysis of the organic compounds fulvic acid, humic acid, and humin in different peat and sapropel extracts from Lithuania was performed in this study. The dominant organic compound was bis(tert-butyldimethylsilyl) carbonate, which varied from 6.90% to 25.68% in peat extracts. The highest mass fraction of malonic acid amide was in the sapropel extract; it varied from 12.44% to 26.84%. Significant amounts of acetohydroxamic, lactic, and glycolic acid derivatives were identified in peat and sapropel extracts. Comparing the two extraction methods, it was concluded that active maceration was more efficient than ultrasound extraction in yielding higher amounts of organic compounds. The highest amounts of fulvic acid (1%) and humic acid and humin (15.3%) were determined in pure brown peat samples. This research on humic substances is useful to characterize the peat of different origins, to develop possible aspects of standardization, and to describe potential of the chemical constituents.


Assuntos
Álcalis/química , Benzopiranos/análise , Benzopiranos/química , Substâncias Húmicas/análise , Solo/química , Cromatografia Gasosa-Espectrometria de Massas
6.
Ecotoxicol Environ Saf ; 220: 112369, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34090109

RESUMO

Soil salinization seriously restricts the growth and yield of soybeans. However, little information is available on the early growth stages of soybeans which are subjected to the gibberellin biosynthesis inhibitor, prohexadione-calcium (Pro-Ca). This study aimed to investigate the effects of exogenous Pro-Ca on saline-alkali stress-induced damages to photosynthesis and antioxidant defenses in soybean (Glycine max L.) seedlings. At the V3 growth stage, salt-tolerant genotype Hefeng 50 (HF50) and salt-sensitive genotype Kenfeng 16 (KF16) were subjected to 110 mmol L-1 mixed saline-alkali stress respectively, and then 100 mg L-1 Pro-Ca was sprayed on the leaves. Our results showed that saline-alkali stress accelerated the degradation of thylakoids, inhibited chlorophyll synthesis, reduced shoot dry weight, electron transfer rate (ETR), and peroxidase (POD) activity, the concentration of ascorbic acid (AsA) and soluble sugar, but enhanced the concentration of proline, hydrogen peroxide (H2O2) and the rate of superoxide radical (O2∙-) generation. Additionally, saline-alkali stress induced a lower decrease of the net photosynthetic rate (Pn), potential activity of PSII (Fv/F0), and maximum quantum yield of PSII (Fv/Fm) in salt-tolerant HF50 than in salt-sensitive KF16. Nevertheless, foliar spraying of exogenous Pro-Ca increased the chlorophyll content, Pn, Fv/F0, and Fv/Fm. These results were more prominent when Pro-Ca was applied to KF16 under saline-alkali conditions. Furthermore, exogenous application of Pro-Ca retarded the degradation of thylakoids, increased the ETR and the accumulation of AsA, soluble sugar, and proline, activated the activities of superoxide dismutase (SOD), catalase (CAT), and POD, and decreased the concentration of malondialdehyde (MDA), electrolyte leakage (EL), O2∙-, and H2O2. These results indicated that Pro-Ca could effectively protect soybean seedlings against damage from saline-alkali stress by regulating seedling phenotype, photosynthetic apparatus, antioxidant defense, and osmoregulation.


Assuntos
Álcalis/toxicidade , Antioxidantes/metabolismo , Ácidos Cetoglutáricos/farmacologia , Fotossíntese/efeitos dos fármacos , Soja/efeitos dos fármacos , Clorofila/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Soja/crescimento & desenvolvimento , Soja/metabolismo , Estresse Fisiológico/efeitos dos fármacos , Tilacoides/metabolismo
7.
Ying Yong Sheng Tai Xue Bao ; 32(5): 1799-1806, 2021 May.
Artigo em Chinês | MEDLINE | ID: mdl-34042376

RESUMO

Solid waste-based improver is one of the effective means to improve properties of saline-alkali soil. As a kind of porous waste, activated coke is expected to improve soil properties and alleviate salt-alkali stress. In order to understand the improvement effect of activated coke on saline alkali land in northern Shanxi Province, we examined the effects of different addition rates of activated coke (CK, 0 g·kg-1; A10, 10 g·kg-1; A20, 20 g·kg-1; A50, 50 g·kg-1) on the properties of saline alkali soil and the growth of two plant species. The results showed that activated coke addition could increase the content of water soluble soil aggregates, reduce soil salt content, soil pH, and the electrical conductivity (EC). Compared with CK, the mean weight diameters of the aggregates for the saline-alkali soils grown with Puccinellia distans and maize were increased by 5.1%-32.2%, soil pH was decreased by 0.4%-4.1%, sodium adsorption ratio (SAR) was decreased by 4.8%-18.7%, and the EC was decreased by 7.4%-8.2%. Applying appropriate amount of activated coke could promote plant growth through reducing the plasma membrane damage of plant cells, increasing plant chlorophyll and Ca2+ contents. The biomass of Puccinellia distans and maize both reached the maximum under the A20 treatment. It suggested that the application of 20 g·kg-1 activated coke (A20) in saline alkali soil could improve soil quality in the rhizosphere soil, increase plant selective Ca2+ absorption, thereby reducing salt damage to plant cells and promote plant growth in saline-alkali habitat.


Assuntos
Coque , Solo , Álcalis , China , Rizosfera
8.
Food Chem ; 360: 130001, 2021 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-34000631

RESUMO

Food processing might induce the transformation of hidden ZEN (zein-bound ZEN) in maize. The objective of this study was to assess the effect of processing factors on free ZEN and hidden ZEN. After zein was treated under different temperature and pH, ZEN was quantified in samples before and after in vitro digestion. The ratios of hidden to total ZEN in zein are decreased from 54.25% to 40.74% after thermal treatment and from 54.25% to 0 after alkaline treatment, respectively. Conversely, acid treatment increased the ratio of hidden to total ZEN from 54.25% to 100%. Thus, it can be concluded that thermal or alkaline condition induced the conversion of hidden ZEN to free ZEN while acid condition promoted the ZEN-zein interactions to form the hidden ZEN. Overall, temperature and pH values played a vital role in the conversion of hidden ZEN during food processing.


Assuntos
Zearalenona/análise , Zeína/química , Ácidos/química , Álcalis/química , Cromatografia Líquida de Alta Pressão , Digestão , Manipulação de Alimentos , Concentração de Íons de Hidrogênio , Estabilidade Proteica , Espectrometria de Massas em Tandem , Temperatura , Zea mays/metabolismo , Zeína/metabolismo
9.
Transl Vis Sci Technol ; 10(3): 6, 2021 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-34003940

RESUMO

Purpose: Chemical burns due to alkalis cause extensive damage to the ocular surface leading to blindness. Assessment of ocular burn could be challenging due to severe opacity, inflammation, and angiogenesis. Anterior segment optical coherence tomography (AS-OCT) and OCT angiography (OCTA) may provide fast, non-invasive deep tissue visualization of pathology with high sensitivity in conjunction with slit-lamp analysis. Methods: C57-BL/6J mice were anesthetized with ketamine/dexmedetomidine, and corneal alkali burn was induced (n = 6) by placing filter paper soaked in 1-M sodium hydroxide for 30 seconds on the right eye while the left eye was kept as control. Longitudinal imaging was done with AS-OCT/OCTA and fluorescein angiography at various time intervals for 14 days. Results: AS-OCT showed characteristic pathological changes in alkali-burned eyes with high sensitivity. Although OCT/OCTA showed three-dimensional and cross-sectional views of the anterior chamber and angiogenesis, fluorescein angiography showed nascent vessels with active leakage. Corneal swelling progressively increased by 125.26% on day 12 with a high prevalence of epithelial bullae, stromal cysts, stromal splitting, and Descemet's membrane detachment. Neovascularization was noted as early as day 4 in the burned eyes by both methods. Severe corneal opacity and anterior chamber inflammation were also detected by AS-OCT/OCTA. Conclusions: AS-OCT/OCTA is a promising, noninvasive, high-resolution imaging modality that can provide both qualitative and quantitative information regarding deep tissue pathology at a structural level. Translational Relevance: Noninvasive AS-OCT/OCTA and fluorescein methods show promise in clinical pathology evaluation for ocular injury management and prognostic indications, as the early presence of Descemet's membrane detachment and corneal swelling appears to be correlated with the severity and localization of corneal neovascularization.


Assuntos
Álcalis , Tomografia de Coerência Óptica , Animais , Córnea/diagnóstico por imagem , Estudos Transversais , Angiofluoresceinografia , Camundongos
10.
Artigo em Inglês | MEDLINE | ID: mdl-33999794

RESUMO

A haloalkaliphilic hydrolytic actinobacterium, strain ACPA22T, was enriched and isolated in pure culture from saline alkaline soil (soda solonchak) in northeastern Mongolia. The isolate was facultatively alkaliphilic, growing at pH 6.5-10.5 (optimum at 7.3-9.0) and highly salt-tolerant, tolerating up to 3 M total Na+ as carbonates. The hydrolytic nature of ACPA22T was confirmed by two different growth-dependent methods and by the presence of multiple glycosidase-encoding genes in the genome. The 16S rRNA gene-based phylogenetic analysis demonstrated that strain ACPA22T formed a deep-branching lineage within the family Glycomycetaceae, with the highest sequence similarity value to Glycomyces buryatensis 18T (92.1 %) and Salininema proteolyticum Miq-4T (91.8 %). The average amino acid identity values (56.1-61.5 %) between ACPA22T and other Glycomycetaceae members with available genomes did not exceed the threshold reported for different genera. The cell wall of ACPA22T contained meso-diaminopimelic acid, glycine, glutamic acid and alanine in a molar ratio, characteristic of the peptidoglycan type A1γ'. The whole-cell sugars included mannose, galactose, arabinose, ribose and xylose. The major menaquinones were MK-10(Н4) and MK-11(Н4). The identified polar lipids were represented by phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannosides. In addition, the strain had a few unidentified characteristic polar lipids, including an amine-containing phospholipid with chromatographic mobility similar to that of phosphatidylinositol. The polar lipid fatty acids were dominated by anteiso-C17 : 0 and iso-C16 : 0. The genome included a chromosome of 3.94 Mbp (G+C content 61.5 mol%) encoding 3285 proteins and two plasmids of 59.8 and 14.8 kBp. Based on the data obtained in this study, a new genus and species, Natronoglycomyces albus gen. nov., sp. nov, is proposed with the type strain ACPA22T (=DSM 106290T=VKM Ac-2771T).


Assuntos
Actinobacteria/classificação , Filogenia , Microbiologia do Solo , Actinobacteria/isolamento & purificação , Álcalis , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Graxos/química , Mongólia , Peptidoglicano/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Solo/química , Vitamina K 2/química
11.
J Chromatogr A ; 1648: 462187, 2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-33975083

RESUMO

A novel polymer-based weak cation exchanger (WCX) for ion chromatography has been described. It was prepared by grafting tert-butyl acrylate and maleic anhydride onto the surface of poly(glycidyl methacrylate-divinylbenzene) microspheres via atom transfer radical polymerization, followed by hydrolytic treatment to produce acrylic and maleic acid groups. The obtained WCX showed better separation and higher selectivity for model cations relative to solely acrylic or maleic acid. Simultaneous separation of alkali and alkaline earth cations (including NH4+) was achieved in a single isocratic run under suppressed mode, and ion exchange was found to dominate the separation process. Its utility was demonstrated for determination of several cations in a beer sample and the recovery was ranging from 98.4 to 109.9%.


Assuntos
Resinas de Troca de Cátion/química , Cromatografia por Troca Iônica/métodos , Polímeros/química , Álcalis/química
12.
Food Chem ; 360: 129967, 2021 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-33984562

RESUMO

Due to the hindrance of flocculated polymers and bacterial cell wall, the production of Bacillus subtilis using monosodium glutamate byproduct (MSGB) was low. With the assistance of scanning electron microscope images, effects of alkali, lysozyme, papain, ultrasound, and their combinations on MSGB were evaluated using the results of soluble protein, carbohydrate, monosaccharides and peptidoglycans. Alkali could dissolve flocculated polymers increasing 21% soluble MSGB, and thus enhanced the subsequent treatments (ultrasound, lysozyme, or papain) to increase 14-17% soluble MSGB. As ultrasound mainly released intercellular components (mannose, and glucose) while lysozyme or papain mainly released cell wall components (peptidoglycans), the combination of alkali, ultrasound, and enzymes led to a highest soluble MSGB (78%), yielding a maximal B. subtilis production of 6.6 × 109 colony-forming units mL-1. This yield was about 33 times that of using untreated MSGB, and the key to improve B. subtilis production was the release of carbohydrate.


Assuntos
Álcalis/farmacologia , Bacillus subtilis/efeitos dos fármacos , Muramidase/farmacologia , Papaína/farmacologia , Glutamato de Sódio/química , Ondas Ultrassônicas , Bacillus subtilis/crescimento & desenvolvimento , Bacillus subtilis/metabolismo , Biotecnologia , Manose/metabolismo
13.
Waste Manag ; 130: 1-11, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34044359

RESUMO

The feasibility of the extensive recycling of waste glass in alkali-activated materials (AAMs) was evaluated. The waste glass was utilised in AAMs for two purposes: a partial activator and a mineral precursor. The waste glass was blended with commercial sodium hydroxide and then heated to produce the solid activator powder. The technical performance of waste glass-based activator was investigated to replace commercial sodium silicate, a common alkali-activator used in AAMs. The effect of waste glass using only as the activator (WGA) and using as both activator and precursor (WGAP) in fly ash/slag-based one-part AAMs was studied using strength and microstructure characterisations. A mass-cost and emission analysis of waste glass-based AAMs (WGA and WGAP) was conducted, comparing the results with ordinary Portland cement (OPC). Characterisation tests of waste glass-based activator showed the effective formation of sodium silicate minerals with the adequate dissolution of activator in water by releasing reactive alkali and silica. Both WGA and WGAP showed comparable strengths at 56 days with a denser microstructure under ambient curing. According to mass analysis, waste glass could be utilised up to 17% by mass of total binder. Based on the analysis of cost and CO2 emissions, WGA and WGAP are around 23% and 15% cheaper and 84% and 82% greener than OPC. The dual role of waste glass in AAMs as an activator and as a precursor broadens the recycling of glass waste in the cement industry by favouring technical and environmental outcomes.


Assuntos
Álcalis , Materiais de Construção , Cinza de Carvão , Vidro , Reciclagem
14.
Bioresour Technol ; 335: 125260, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34015566

RESUMO

The present work was focused on the investigation of lignin isolation from saw industry biomass (sawdust (SD)) using alkali solution, and to perform economic analysis for 2000 kg/batch hypothetical plant using techno-economic analysis. The isolated lignin was fractionated using organic solvent to obtain purified lignin. FTIR and 1H NMR analysis were performed to examine the structural characteristics of lignin. Lignin nanoparticles (LN) showed higher total phenolic content (TPC) (244.1 ± 2 µg of GAE per mg) and antioxidant activity (63.2 ± 1.7%) compared with crude lignin (CL), ethanol fractionated lignin (EL), and acetone fractionated lignin (AL). SuperPro designer was exposed to design and simulated 2000 kg/batch of sawdust fractionation process. The techno-economic analysis estimated that the lignin production cost is about $ 487,000 per year, and the annual revenue could be $ 1,850,000 per year. The techno-economic analysis and sensitivity analysis could be useful for the industrial level sawdust fractionation process.


Assuntos
Álcalis , Lignina , Fracionamento Químico , Análise Custo-Benefício , Resíduos Industriais
15.
J Colloid Interface Sci ; 599: 631-641, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33979745

RESUMO

The advanced oxidation process (AOPs) has caused great concern in recent years. Among them, biochar has been widely studied as a catalyst for advanced oxidation process because of its low price and low environmental risk. In this study, a novel ball milling assisted KOH activation biochar (MKBC) was prepared and applied in peroxydisulfate (PDS) activation to degrade tetracycline hydrochloride (TC-H). In comparison with the oxidation (3.48%) by PDS alone and adsorption (36.19%) by MKBC alone, the removal rate of TC-H was increased to 84.15% in the MKBC/PDS system, indicating that MKBC can successfully activate PDS. Besides, the catalytic activity of the MKBC to activate PDS for the degradation of TC-H is 58.33% higher than that of pristine biochar (PBC). In addition, MKBC has outstanding stability that after three repeated experiments, the removal rate of TC-H by the MKBC/PDS system still remains 77.35%. Meanwhile, the mechanism was investigated that the singlet oxygen (1O2) seized the principal position in the degradation of TC-H in the PDS/MKBC system. This study explored a novel, solvent-free and economic method to propose this extraordinary biochar, which provided a new strategy for the future research of biochar.


Assuntos
Tetraciclina , Poluentes Químicos da Água , Álcalis , Carvão Vegetal , Soja
16.
Food Chem ; 355: 129650, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-33799245

RESUMO

In this study, structural characteristics and formation mechanism of Mesona chinensis polysaccharide (MCP)-whey protein isolate (WPI) gels including group and molecular changes, intermolecular forces, crystallinity, and moisture migration were investigated under pH shifting conditions. Results showed that MCP and WPI formed a stable gel at pH 10. The free sulfhydryl groups and surface hydrophobicity of the MCP-WPI gels increased with the increasing pH. Hydrophobic and hydrogen bond interactions were the main molecular forces involved in the MCP-WPI gels, and electrostatic interactions and disulfide bonds played a complementary role. The pH conditions evidently influenced the secondary conformational structure of MCP-WPI gels. Molecular weight and X-ray diffraction (XRD) analysis indicated the formation of a hypocrystalline complex with molecular interaction. In addition, low-field magnetometry (LF-NMR) results showed that the T2 values decreased with increasing pH, indicating that water and gel matrix had the highest interactions at pH 10.


Assuntos
Álcalis/química , Lamiaceae/química , Polissacarídeos/química , Proteínas do Soro do Leite/química , Géis , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Reologia , Água/química
17.
Environ Sci Technol ; 55(10): 7015-7024, 2021 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-33905246

RESUMO

This work proposed an innovative and energy-efficient Donnan Dialysis (DD) and Osmotic Distillation (OD) hybrid process for alkali-driven ammonium recovery from wastewater. The efficiency and feasibility of ammonium removal and recovery from synthetic and real wastewater using NaOH and waste alkali were investigated. Ammonium in the feed first transported across the cation exchange membrane and accumulated in the receiver chamber. It is then deprotonated as ammonia, passing through the gas permeable membrane and finally is fixed as ammonium salt in the acid chamber. Our results indicated that employing waste alkali (red mud leachate) as driving solution led to excellent ammonium recovery performances (recovery efficiency of >80%), comparable to those of NaOH solution. When the initial ammonium concentration was 5 and 50 mM, the waste alkali driven DD-OD process achieved acceptable NH4+-N flux density of 16.8 and 169 g N m-2 d-1, at energy cost as low as 8.38 and 2.06 kWh kg-1 N, respectively. Since this alkali driven DD-OD hybrid process is based on solute concentration (or partial pressure) gradient, it could be an energy-effective technology capable of treating wastewaters containing ammonium using waste alkali to realize nutrients recovery in a sustainable manner.


Assuntos
Compostos de Amônio , Destilação , Álcalis , Membranas Artificiais , Osmose , Diálise Renal , Águas Residuárias
18.
Int J Biol Macromol ; 182: 938-949, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33878362

RESUMO

The continuing increase in the global saline-alkali land area has made saline-alkali stress the principal abiotic stress limiting plant growth. Potato is the most important non-grain crop, and its production is also severely limited by saline-alkali stress. However, few studies have addressed the mechanism of saline-alkali tolerance of potato with a focus on its response to neutral salt NaCl stress, or its response to alkali stress. Recently, miRNA-mRNA analyses have helped advance our understanding of how plants respond to stress. Here, we have characterized the morphological, physiological, and transcriptome changes of tissue culture seedlings of potato variety "Qingshu No. 9" treated with NaHCO3 (for 0, 2, 6, and 24 h). We found that the leaves of tissue culture seedlings wilted and withered under alkali stress, and the contents of ABA, BRs, trehalose, and lignin in roots increased significantly. The contents of GAs decreased significantly. Subsequently, miRNA-seq analysis results identified 168 differentially expressed miRNAs (DEMIs) under alkali stress, including 21 exist miRNAs and 37 known miRNAs from 47 families and 110 novel miRNAs. The mRNA-seq results identified 5731 differentially expressed mRNAs (DEMs) under alkali stress. By miRNA-mRNA integrated analysis, were obtained 33 miRNA-target gene pairs composed of 20 DEMIs and 33 DEMs. Next, we identified the "phenylpropanoid biosynthesis", "plant hormone signal transduction", and "starch and sucrose metabolism" pathways as necessary for potato to respond to alkali stress. miR4243-x and novel-m064-5p were involved in the response of potato to alkali stress by their negative regulatory effects on shikimate O-hydroxycinnamoyltransferase (HCT) and sucrose-phosphate synthase (SPS) genes, respectively. The expression results of miRNA and mRNA were verified by quantitative real-time PCR (qRT-PCR). Our results clarify the mechanism of potato response to alkali stress at the miRNA level, providing new insights into the molecular mechanisms of potato's response to alkali stress. We report many candidate miRNAs and mRNAs for molecular-assisted screening and salt-alkali resistance breeding.


Assuntos
Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes , MicroRNAs/genética , RNA Mensageiro/genética , Solanum tuberosum/genética , Estresse Fisiológico , Álcalis/toxicidade , MicroRNAs/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , RNA Mensageiro/metabolismo , Solanum tuberosum/metabolismo , Transcriptoma
19.
Molecules ; 26(5)2021 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-33806418

RESUMO

In topic-related literature pertaining to the treatment of water, there is a lack of information on the influence of iron ions in highly basic polyaluminum chlorides on the efficiency of purifying water with increased contents of organic substance. The aim of this work was to determine the changes in the content of organic substances as well as iron compounds in water intended for human consumption following unit treatment processes with particular attention paid to the coagulation process. As coagulants, polyaluminium chloride PAXXL10 with an alkalinity of 70%, as well as polyaluminium chloride PAXXL1911 with an alkalinity of 85% the composition of which also contained iron, were tested. The analysis of the obtained results showed that iron compounds and organic substances were removed to the greatest extent by the coagulation process, which also had a significant influence on the final efficiency of water treatment. The effectiveness of water treatment was determined by the type of tested polyaluminum chloride, which influenced the formation of iron-organic complexes. The reason behind the formation of colored iron-organic complexes during coagulation using PAXXL1911 coagulant was the high pH (approx. 8), at which the functional groups of organic substances, due to their dissociation, are more reactive in relation to iron, and possibly the fact of introducing additional iron ions along with the coagulant.


Assuntos
Álcalis/química , Hidróxido de Alumínio/química , Ferro/isolamento & purificação , Compostos Orgânicos/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Concentração de Íons de Hidrogênio
20.
Chemosphere ; 279: 130558, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33887596

RESUMO

Soil pollution, caused by heavy metals, is an environmental problem that requires an urgent solution in China. Chemical passivation is a technology that uses various passivators to reduce the availability of heavy metals in soil and realize the remediation of contaminated soil. In this study, we examined the effects of fly ash (FA), alkali-fused fly ash (AFFA), swine manure biochar (SB), and modifying biochar (MB) on the leachability of Cu, Zn, Pb, and Cd via soil culture experiments. The results showed that the addition of AFFA, SB, and MB significantly reduced the extractable contents of Cu, Pb, and Cd in the soil. AFFA and MB had the best passivation effect, followed by SB and FA. The passivation effect on Pb was the best, followed by that on Cu and Cd. AFFA modification significantly improved the passivation effect of MB on Cu, Pb, and Cd in composite contaminated soil. With the addition of 3% MB, the Pb, Cu, and Cd extracted by TCLP decreased by 95.7, 74.1, and 59.1%, respectively. Correlation analysis, Fourier transform infrared spectrometry, scanning electron microscopy, and energy-dispersive X-ray spectroscopy showed that the passivation mechanism is mainly due to an increase in the soil pH, silicate content, and cohesiveness. The soil culture experiments in this study proved that MB is a low-cost and highly efficient organic-inorganic composite passivator for multi-metal contaminated soils.


Assuntos
Metais Pesados , Poluentes do Solo , Álcalis , Animais , China , Cinza de Carvão , Esterco , Metais Pesados/análise , Solo , Poluentes do Solo/análise , Suínos
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