Isobutanol Research Articles

Integrative metagenomics, volatilomics and chemometrics for deciphering the microbial structure and core metabolic network during Chinese rice wine (Huangjiu) fermentation in different regions

Huangjiu is a spontaneously fermented alcoholic beverage, that undergoes intricate microbial compositional changes. This study aimed to unravel the flavor and quality formation mechanisms based on the microbial metabolism of Huangjiu. Here, metagenome techniques, chemometrics analysis, and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC–MS) metabolomics combined with microbial metabolic network were employed to investigate the distinctions and relationship between the microbial profiles and the quality characteristics, flavor metabolites, functional metabolic patterns of Huangjiu across three regions. Significant variations (P < 0.05) were observed in metabolic rate of physicochemical parameters and biogenic amine concentration among three regions. 8 aroma compounds (phenethyl acetate, phenylethyl alcohol, isobutyl alcohol, ethyl octanoate, ethyl acetate, ethyl hexanoate, isoamyl alcohol, and diethyl succinate) out of 448 volatile compounds were identified as the regional chemical markers. 25 dominant microbial genera were observed through metagenomic analysis, and 13 species were confirmed as microbial markers in three regions. A metabolic network analysis revealed that Saccharomycetales (Saccharomyces), Lactobacillales (Lactobacillus, Weissella, and Leuconostoc), and Eurotiales (Aspergillus) were the predominant populations responsible for substrate, flavor (mainly esters and phenylethyl alcohol) metabolism, Lactobacillales and Enterobacterales were closely linked with biogenic amine. These findings provide scientific evidence for regional microbial contributions to geographical characteristics of Huangjiu, and perspectives for optimizing microbial function to promote Huangjiu quality.

New strategy for structure rearrangement of thin-film composite (TFC) polyamide (PA) membranes and offering potential use in both aqueous and organic solvents

The purity of sodium hexafluorophosphate (NaPF6) is crucial for the preparation of electrolytes in manufacturing. We propose a simple process in order to induce membrane structure rearrangement process (SRP) by activating thin-film composite (TFC) membranes with polyamide (PA) structure and explore their potential green recycling application in concentrating sodium-ion batteries (SIBs) electrolyte. The method utilizes a solution containing polar aprotic solvent as the soaking and activating solution to swell and disintegrate the loosely cross-linked PA layer, and a non-solvent solidification solution complete the SRP, enhancing the permeability of the PA layer while maintaining high rejection rates for divalent ions. Subsequently, during the further treatment of the membrane surface in structure rearrangement, tert-butanol (TBA) is introduced into the aqueous solution to reconstruct the surface PA layer, further improving the permeability. The optimal D8010T10 achieved a permeation flux of 24.2 L m−2 h−1·bar−1, with rejection rates for sodium sulfate (Na2SO4), magnesium chloride (MgCl2), and magnesium sulfate (MgSO4) reaching 94.7 %, 98.4 %, and 99.1 % respectively. And the mechanism of SRP with different solvent is analyzed and explained through dissipative particle dynamics (DPD) simulations. This study provides a commercially viable approach for manufacturing high-performance membranes. The D8010T10 membrane achieves more than 90 % separation efficiency for sodium hexafluorophosphate (NaPF6) dissolved in different solvents, providing a potential solution for the concentration and recovery of NaPF6 in lab-scale, verified its potential use in the organic solvent nanofiltration (OSN) and a path way for waste membrane recycling and degrading use in the industry.

Constructing High-Active Surface of Plasmonic Tungsten Oxide for Photocatalytic Alcohol Dehydration.

Plasmonic semiconductors with broad spectral response hold significant promise for sustainable solar energy utilization. However, the surface inertness limits the photocatalytic activity. Herein, a novel approach is proposed to improve the body crystallinity and increase the surface oxygen vacancies of plasmonic tungsten oxide by the combination of hydrochloric acid (HCl) regulation and light irradiation, which can promote the adsorption of tert-butyl alcohol (TBA) on plasmonic tungsten oxide and overcome the hindrance of the surface depletion layer in photocatalytic alcohol dehydration. Additionally, this process can concentrate electrons for strong plasmonic electron oscillation on the near surface, facilitating rapid electron transfer within the adsorbed TBA molecules for C-O bond cleavage. As a result, the activation barrier for TBA dehydration is significantly reduced by 93% to 6.0kJ mol-1, much lower than that of thermocatalysis (91kJ mol-1). Therefore, an optimal isobutylene generation rate of 1.8mol g-1 h-1 (selectivity of 99.9%) is achieved. A small flow reaction system is further constructed, which shows an isobutylene generation rate of 12mmol h-1 under natural sunlight irradiation. This work highlights the potential of plasmonic semiconductors for efficient photocatalytic alcohol dehydration, thereby promoting the sustainable utilization of solar energy.

Heterojunction-Based Photocatalytic Degradation of Rose Bengal Dye via Gold-Decorated α-Fe2O3-CeO2 Nanocomposites under Visible-Light Irradiation

Developing photocatalytic nanomaterials with unique physical and chemical features using low-cost and eco-friendly synthetic methods is highly desirable in wastewater treatment. In this work, the magnetically separable α-Fe2O3-CeO2 nanocomposite (NC), with its respective metal oxides of α-Fe2O3 and CeO2 nanoparticles, was synthesized using a combination of hexadecyltrimethylammonium bromide (CATB) and ascorbic acid via the hydrothermal method. To tune the band gap, the heterojunction nanocomposite of α-Fe2O3-CeO2 was decorated with plasmonic Au nanoparticles (Au NPs). The various characterization methods, such as FTIR, UV-vis DRS, XRD, XPS, TEM, EDX, SEM, and PL, were used to determine the properties of the materials, including their morphology, elemental composition, optical properties, band gap energy, and crystalline phase. The nanocomposite of α-Fe2O3-CeO2@Au was utilized to remove Rose Bengal (RB) dye from wastewater using a photocatalytic technique when exposed to visible light. A comprehensive investigation of the impact of the catalyst concentration and initial dye concentration was conducted to establish the optimal photodegradation conditions. The maximum photocatalytic efficiency of α-Fe2O3-CeO2@Au (50 mg L−1) for RB (20 ppm) dye removal was found to be 88.9% in 120 min under visible-light irradiation at a neutral pH of 7 and 30 °C. Various scavengers, such as benzoquinone (BQ; 0.5 mM), tert-butyl alcohol (TBA; 0.5 mM), and ethylenediaminetetraacetic acid (EDTA; 0.5 mM), were used to investigate the effects of different free radicals on the photocatalytic process. Furthermore, the reusability of the α-Fe2O3-CeO2@Au photocatalyst has also been explored. Furthermore, the investigation of the potential mechanism demonstrated that the heterojunction formed between α-Fe2O3 and CeO2, in combination with the presence of deposited Au NPs, led to an enhanced photocatalytic efficiency by effectively separating the photogenerated electron (e−)–hole (h+) pairs.

Effect of adsorption/desorption of substrates/products during isobutyl propionate synthesis over CalB Immo Plus™ in solid/gas biocatalysis

This work revisits the potential of Solid/Gas (S/G) biocatalysis for sustainable ester synthesis, focusing on isobutyl propionate (isoPro) production from propionic acid (aciP) and isobutyl alcohol (isoB) using CalB Immo Plus™ (CalB-IP), Candida antarctica lipase B (CalB) supported on ECR1030M (ECR). Our research, conducted in a bench-scale S/G bioreactor, describes the role of adsorption-desorption and intraparticle mass transfer on the production rate of isoPro. Three reaction scenarios were examined at 55°C: simultaneous introduction of both substrates into the reactor; CalB-IP saturation with isoB followed by the supply of aciP; and vice versa, with aciP saturation preceding isoB. Adsorption-desorption-based experiments were conducted to determine breakthrough curves for isoB, aciP, and isoPro over ECR or CalB-IP at 55°C. ECR exhibited significant adsorption capacity, with aciP>isoPro>isoB, in a reversible process. At pseudo-steady state, aciP and isoB were adsorbed at 86% and 84%, respectively, on ECR; while the remaining 14% and 16%, respectively, were adsorbed on the enzyme surface, involving irreversible binding. The experimentation also considered the influence of water activity (aw: 0.11–0.75) on experimental responses. Production rates of isoB adsorption and isoPro were sensitive to aw, while aciP adsorption remained insensitive to aw. At aw = 0.75, isoB adsorbed 35% less over CalB-IP than at aw = 0.11. Additionally, at aw = 0.75, the production of isoPro at the bioreactor outlet in the pseudo-steady state was 33.5% less than when aw = 0.11. These findings offer valuable insights for designing S/G bioreactors, thereby advancing the industrial implementation of sustainable ester synthesis.

Construction of β-Oximino Phosphorodithioates via (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl-Promoted Difunctionalization of Alkenes with tert-Butyl Nitrite, P4S10, and Alcohols.

A (2,2,6,6-tetramethylpiperidin-1-yl)oxyl-mediated difunctionalization of alkenes with tert-butyl nitrite, P4S10, and alcohols has been developed for the synthesis of β-oximino phosphorodithioates. The reaction goes through a radical pathway with the successive installation of phosphorodithioate and an oxime group. This four-component protocol offers a practical approach to constructing a variety of β-oximino phosphorodithioates in moderate to good yields with favorable functional group tolerance.

Experimental and mechanism study on the separation of isobutyl alcohol and water azeotrope using hydrophobic deep eutectic solvents

Isobutyl alcohol with good miscibility, high octane number and energy density has been paid more and more attention in the field of new biofuels, as it is an ideal alternative fuel for gasoline. However, isobutyl alcohol and water azeotrope need a clean and efficient separation method to realize the separation in isobutyl alcohol production process and industrial wastewater. Three hydrophobic deep eutectic solvents (DESs) were used to separate isobutyl alcohol. Decanoic acid was used as hydrogen bond donor and menthol, thymol and lidocaine were used as hydrogen bond acceptors to synthesize DESs. The liquid-liquid equilibrium experiment was carried out for the system containing DESs and MSD −water at 101.3 kPa and 303.15 K, and the separation effect of different DESs was indicated using distribution coefficient (β) and selectivity (S). The σ-Profile can be a good reflection of the strength of a substance's ability to accept and provide hydrogen bonds. The interaction energy and self-diffusion coefficient of the separation system were described quantitatively by molecular dynamics simulation. The relationship between DESs and the separation system was analyzed quantitatively by radial distribution function and spatial distribution function. The separation results show that the three DESs have good separation effect on isobutyl alcohol-water system, among which the DESs synthesized by thymol and decanoic acid has the best separation effect, and the interaction of isobutyl alcohol-water separation process is controlled by van der Waals forces. DESs plays an important role in the separation and treatment of isobutyl alcohol-containing wastewater, and promotes the sustainable development of wastewater treatment projects to save costs and increase production benefits.

A Study of Condensates Collected during the Fermentation of Grape Must

This article deals with the analysis of the condensates which are formed from fermentation gases during the fermentation of grape must. The experiment was divided into two parts. In the first part, the evolution of the individual volatiles was monitored throughout the whole fermentation process of the Riesling variety. In the second part, the condensates from three different grape varieties (Riesling, Merlot, Sauvignon blanc) were investigated and the total content of the selected volatile substances was measured at the end of the fermentation. Attention was focused on the measurements using a GC-MS (gas chromatography-mass spectrometry) for the volatile substances: isoamyl alcohol, isobutyl alcohol, 1-propanol, ethyl acetate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, acetaldehyde, acetic acid, and acetoin. In addition, changes in the alcohol content of the condensate, with respect to the fermentation phase, were analysed. From the results of part 1, the quantity of the substances under investigation produced during fermentation was determined. The highest concentration of flavour compounds was during the fourth and fifth days of fermentation. The most dominant substance was isoamyl alcohol with a concentration of 1267 mg−1.The results of part 2 led to a comparison of the overall profile of volatiles between the varieties. The results showed that the condensates have both a high content of volatile substances and of alcohol. It was also shown that the Sauvignon blanc variant had the highest number of volatile compounds in the representation. The Merlot and Riesling variants were very similar. This product has an exceptionally high potential for further use in the wine or food industry.

Economic, environmental, energy, exergy (4E) analysis and simulated annealing algorithm optimization of dividing-wall column-intensified heterogeneous azeotropic pressure-swing distillation process

This work presents an approach for the recovery of high purity cyclohexane (CYCLO) and tertiary butyl alcohol (TBA) from wastewater. After thermodynamic analysis, a heterogeneous azeotrope-pressure swing distillation process (HAPSD) with a decanter is proposed. The heterogenous azeotrope distillation with a high-pressure column and a dividing-wall column process (HADWC) is also being developed to propose a green and sustainable process. The novel processes are optimized using simulated annealing algorithm (SAA). Those processes are optimized by simulated annealing algorithm by linking Aspen Plus and MATLAB via taking the total annual cost (TAC) as objective function. Three energy-efficient HADWC processes are proposed based on the process intensification approach of heat pump and heat integration technologies. All processes are evaluated for multi-criteria performance including economy, energy consumption, gas emissions and thermodynamic efficiency. As the result, HADWC-HP-HI process shows the best performance with 31.79%, 53.46%, 50.69%, and 57.94% reducing over the conventional HAPSD process in terms of TAC, energy consumption, gas emissions and thermodynamic efficiency, respectively.

Kinetic Study of Manganese Oxidative Precipitation Reaction by Using SO2/Air Gas Mixture

Removing manganese from zinc electrolytes is necessary to pave the way for replacing lead-based anodes with mixed metal oxide (MMO) anodes. MMO anodes offer significantly lower overpotential towards oxygen evolution reactions, thus are attractive from an energy consumption viewpoint. Previous studies had shown that, thanks to the catalytic effect of cobalt, manganese can be removed successfully from the zinc purification solution through the oxidative precipitation method using a simulated roasting off-gas plant. This study focuses on understanding the primary mechanism behind manganese oxidation precipitation and investigating the influence of various operating parameters such as temperature, dissolved oxygen (DO), and solution potential on the reaction kinetics. The results revealed that the kinetics of the reaction was highly dependent on the temperature and catalyst activity rather than on the reactant concentration. Additives, with radical scavenging effects, were added to identify the radicals responsible for the oxidation of Mn. The manganese oxidation reaction was dramatically suppressed when methanol was added. However, in the presence of tert-butyl alcohol (TBA), a sensible reduction in manganese removal was not observed, suggesting sulfate radical as the predominant species for oxidizing manganese. The physical and chemical characteristics of the sediments were also presented.

Unwinding the correlation between atmospheric pressure plasma jet operating parameters and variation in antibiotic wastewater characteristics

The influence of plasma operating parameters such as gas medium, electrode distance, applied voltage, gas flow rate, and their interdependency on reactive species generation was investigated. Full factorial design-based response surface methodology (RSM) was used to establish the correlation between the operating parameters. The optimization studies were carried out by taking energy yield and degradation efficiency as response parameters. The operating voltage of 9 kV, the airflow rate of 2 LPM, and the electrode distance of 5 mm are optimum for the system studied. The higher voltage of 9 kV and a flow rate of 2 LPM give maximum yield due to the increased rate of gas atoms undergoing ionization. However, at the low voltage (5 kV), the increase in air flow rate from 0.5 to 2 LPM, the energy yield decreases from 67.5 to 54.2 mg/kWh. These observations are further supported by measuring OH (A-X) intensity in an air medium using optical emission spectroscopy. The studies also reveal that the degradation efficiency is adversely affected by scavenges, with a maximum from isopropyl alcohol, followed by tert-butyl alcohol and methanol. TOC and LC-MS analyses established complete mineralization and its degradation pathway. Phytotoxicity studies suggest that treated effluent, rich in nitrates, is suitable for irrigation, promoting seed germination. In short, the studies provide a strategy to optimize the generation of reactive chemical species in a reactor and how such optimization would help attain optimum energy yield, especially when there is a fluctuation in target pollutant concentration.

Comparative description of the extraordinary phenomenon "thermally activated isobaric partial structure compaction" of water as a solute in some alkanols and alkylamines

This review summarises the data available in the literature. It also includes the authors' published results of precision densimetric measurements. The research concerns with the physically unusual phenomenon of "thermally activated isobaric partial densification of the structure" (TIPCS) of dissolved water, or its so-called "negative partial molar expandability" (NPEA) in several organic solvents. They contain amphiproton hydroxyl-containing media of three alcohols: methyl alcohol (MA), tertiary butyl alcohol (TBAlcohol), and amyl or pentyl alcohol (TPA), so asprotophilic media of two amines: tert butylamine (TBAmine) and ethylenediamine (EDA). The discussed TIPCS phenomenon, associated with a decrease in the standard (partial at infinite dilution) volume of solvated water with increasing temperature, was discovered about half a century ago in alkanol solutions of H2O and recently - in water-containing media of alkylamines. However, nowadays this extraordinary effect has not yet found its physically based interpretation. It allows ones to predict the possibility of TIPCS occurrence in the binary liquid-phase system specifically selected for the study. Our comprehensive data analysis allowed us to make several inferences regarding the main characteristics of a standard solution of H2O in an organic solvent. They cause extraordinary changes in the volume of the formed solvatocomplex of water under the influence of increasing temperature. Firstly, the energy parameters of the intermolecular interaction (relative affinity) water solvent noticeably dominate over those of the solvent-solvent interaction. Those differences become more evident with increasing temperature. Secondly, a higher rate of thermal expansion of the organic solvent structure in volume (inbulk) is found than influence of temperature on structural packing of the resulting mixed molecular aggregate or water solvates complex. Thirdly, the difference in the parameters of water-solvent and solvent-solvent interactions depends not only on the proton-donor/acceptor properties of the molecules contacting in solution, but also on the configuration of the structural packing of the solvating medium. It determines the nature of steric hindrances to the formation of H-bonds. Therefore, the absolute values of the mentioned parameters of relative affinity at 298.15 K increase in the series: MA &lt;&lt; EDA ≈ TBAmine &lt; TPAlcohol &lt; TBAmine. It can indicate a relative strengthening of the specific interaction (mainly through the formation of hydrogen bonds) between the molecules of water and amphiprotonic or protophilic solvent in the above sequence. Indeed, difference in the solvent-solvent and water-solvent hydrogen bonding energies in the discussed liquid media of alkylamines (TBAmine and EDA) and tertiary isomeric alkanols (TBAlcohol and TPA) - with the most evident basicity - turned out to be noticeably larger than in the structural packing of water methanol solution. The ability of the components to specific interactions is quite comparable in those compounds.

Сравнительная характеристика неординарного явления «термоактивируемого изобарического парциального уплотнения структуры» воды как растворенного вещества в некоторых алканолах и алкиламинах

This review summarises the data available in the literature. It also includes the authors' published results of precision densimetric measurements. The research concerns with the physically unusual phenomenon of "thermally activated isobaric partial densification of the structure" (TIPCS) of dissolved water, or its so-called "negative partial molar expandability" (NPEA) in several organic solvents. They contain amphiproton hydroxyl-containing media of three alcohols: methyl alcohol (MA), tertiary butyl alcohol (TBAlcohol), and amyl or pentyl alcohol (TPA), so asprotophilic media of two amines: tert butylamine (TBAmine) and ethylenediamine (EDA). The discussed TIPCS phenomenon, associated with a decrease in the standard (partial at infinite dilution) volume of solvated water with increasing temperature, was discovered about half a century ago in alkanol solutions of H2O and recently - in water-containing media of alkylamines. However, nowadays this extraordinary effect has not yet found its physically based interpretation. It allows ones to predict the possibility of TIPCS occurrence in the binary liquid-phase system specifically selected for the study. Our comprehensive data analysis allowed us to make several inferences regarding the main characteristics of a standard solution of H2O in an organic solvent. They cause extraordinary changes in the volume of the formed solvatocomplex of water under the influence of increasing temperature. Firstly, the energy parameters of the intermolecular interaction (relative affinity) water solvent noticeably dominate over those of the solvent-solvent interaction. Those differences become more evident with increasing temperature. Secondly, a higher rate of thermal expansion of the organic solvent structure in volume (inbulk) is found than influence of temperature on structural packing of the resulting mixed molecular aggregate or water solvates complex. Thirdly, the difference in the parameters of water-solvent and solvent-solvent interactions depends not only on the proton-donor/acceptor properties of the molecules contacting in solution, but also on the configuration of the structural packing of the solvating medium. It determines the nature of steric hindrances to the formation of H-bonds. Therefore, the absolute values of the mentioned parameters of relative affinity at 298.15 K increase in the series: MA &lt;&lt; EDA ≈ TBAmine &lt; TPAlcohol &lt; TBAmine. It can indicate a relative strengthening of the specific interaction (mainly through the formation of hydrogen bonds) between the molecules of water and amphiprotonic or protophilic solvent in the above sequence. Indeed, difference in the solvent-solvent and water-solvent hydrogen bonding energies in the discussed liquid media of alkylamines (TBAmine and EDA) and tertiary isomeric alkanols (TBAlcohol and TPA) - with the most evident basicity - turned out to be noticeably larger than in the structural packing of water methanol solution. The ability of the components to specific interactions is quite comparable in those compounds.

Improving the dyeability of ramie fibre by sequential alkaline and alcohol pretreatments

The high crystallinity of ramie fibre poses challenges in achieving optimal dyeing performance, such as reduced dye exhaustion. To enhance the dyeing capabilities of ramie fibre, several alterations were experimented with, such as caustic mercerization using a NaOH solution. However, because of the high NaOH concentration, removing the NaOH residue from inside the fibre becomes challenging. Herein, the present research aims to enhance the dyeing efficiency of ramie fibre by using sequential alkaline and alcohol pretreatment methods to reduce NaOH usage, accordingly relieving the wash process stress. The preliminary screening findings have revealed that iso-butanol is the most suitable alcohol solvent for modifying ramie fibres after treating it with NaOH solution since it leads to higher dye exhaustion (E%, 95.7%), dye fixation rate (F%, 88.2%), total dye fixation efficiency (T%, 84.4%), and K/S values (41.4). After that, the orthogonal array experimental scheme (L16) was applied to optimize dyeing performance. The NaOH usage was decreased to 160 g/L, the treating time was reduced to 3 min, and the dyeing performance of ramie fibre treated under the optimum conditions was better than that of a caustically mercerized one. It was determined that the NaOH concentration factor had the most contribution, accounting for 75.34% of the observed effects. The NaOH solution temperature factor followed closely behind, contributing 22.69%. Additionally, using analytical methods such as XRD, FTIR, TG, and SEM confirmed that the sequential treatment with the optimum conditions altered the structural behaviour of the original ramie fibre, which performances were similar to the mercerized ramie fibre. The barium value of sequentially iso butanol solvent treated fibre showed a greater level (213) compared to caustic mercerized fibre (179), indicating a significant advantage of mercerization performance was achieved. This advantage may be linked to improved colourfastness and handling qualities. Furthermore, the breaking force of both ramie fabrics was increased after the alkaline treatment and the sequential alkaline and iso-butanol treatment.

Assessment of the genotoxicity of tert-butyl alcohol in an in vivo thyroid comet assay.

Chronic exposure to high (20,000 ppm) concentrations of tert-butyl alcohol (TBA) in drinking water, equivalent to ~2100 mg/kg bodyweight per day, is associated with slight increases in the incidence of thyroid follicular cell adenomas and carcinomas in mice, with no other indications of carcinogenicity. In a recent toxicological review of TBA, the U.S. EPA determined that the genotoxic potential of TBA was inconclusive, largely based on non-standard studies such as in vitro comet assays. As such, the potential role of genotoxicity in the mode of action of thyroid tumors and therefore human relevance was considered uncertain. To address the potential role of genotoxicity in TBA-associated thyroid tumor formation, CD-1 mice were exposed up to a maximum tolerated dose of 1500 mg/kg-day via oral gavage for two consecutive days and DNA damage was assessed with the comet assay in the thyroid. Blood TBA levels were analyzed by headspace GC-MS to confirm systemic tissue exposure. At study termination, no significant increases (DNA breakage) or decreases (DNA crosslinks) in %DNA tail were observed in TBA exposed mice. In contrast, oral gavage of the positive control ethyl methanesulfonate significantly increased %DNA tail in the thyroid. These findings are consistent with most genotoxicity studies on TBA and provide mechanistic support for non-linear, threshold toxicity criteria for TBA. While the mode of action for the thyroid tumors remains unclear, linear low dose extrapolation methods for TBA appear more a matter of policy than science.

Removal of Reactive Black 5 by UV-C assisted peroxydisulfate process: Effect of parameters, kinetic study, and phytotoxicity assessment

ABSTRACT Photochemical removal of Reactive Black 5 (RB5) was investigated by the UV-C assisted peroxydisulfate (UV-C/PDS) process. Parameters affecting the removal of RB5 were examined. Activation of PDS by UV-C light significantly improved the removal efficiency compared to direct photolysis or PDS alone. The removal of RB5 by UV-C/PDS process fitted well with the pseudo first-order kinetic model under all tested conditions. Almost complete removal of RB5 was achieved at the end of 120 min within the pH range of 3–7, whereas 90.7 and 89.4% removal efficiency values were observed at pH = 9 and 11, respectively. An increase in PDS dosage in the range of 0.25–1 mM led to a rise in removal from 48.5 to 97.3% after 120 min, and a complete removal was observed with a dosage higher than 2 mM. Pseudo firstorder rate constant (kobs) increased linearly with PDS dosage from 0.0058 to 0.0518 min−1 in the 0.25 mM − 2.3 mM concentration range. The removal efficiency decreased with an increase in the initial concentration of RB5 from 20 to 50 mg L−1 and an exponential correlation was observed between kobs and initial concentration of RB5. Scavenging experiments conducted using t-butyl alcohol and ethyl alcohol implied that both sulphate and hydroxyl radicals were involved in the removal of RB5. Adding HCO3 − decreased the removal of RB5 within the range of 1–30 mM. The presence of CI− showed a negative impact on the removal at low concentrations (1–15 mM) and NO3 − slightly inhibited the removal of RB5. With corresponding stoichiometric PDS dosage, almost a complete mineralisation was achieved for RB5 solution and simulated dyebath effluent after 720 min of reaction time. EE/O values were determined to be 91.0, 76.8, and 41.1 kWh m−3 order−1 for UV-C/H2O2, UV-C/PMS, and UV-C/PDS processes, respectively. The phytotoxicity tests indicated that the intermediates could be more toxic than the parent compound.

Three-Dimensional Electrochemical Oxidation System with RuO2-IrO2/Ti as the Anode for Ammonia Wastewater Treatment

In this study, a three-dimensional electrochemical oxidation system was constructed to treat ammonia nitrogen wastewater generated from the tail gas absorption of a methionine producer by using a homemade MAC mixed with a GAC at a mass ratio of 1:2 as the particle electrode, with a RuO2-IrO2/Ti polar plate as the anode and a stainless steel plate as the cathode. The effects of current density, initial pH value of wastewater, plate spacing, NaCl concentration and particle filling amount on CODCr and NH4+-N removal were investigated through single-factor experiments, and the removal pathways of CODCr and NH4+-N under the system were initially explored via cyclic voltammetry curves, scanning electron microscopy and tertiary butanol quenching experiments. The experimental results showed that the average removal rate of CODCr was 91.03% and that of NH4+-N was 98.89% after electrolysis for 5 h under the conditions of a current density of 40 mA/cm2, no pH adjustment, the spacing of the electrode plates of 8 cm, the NaCl dosing concentration of 1 g/L, and the particle filling amount of 400 g/L. Under this experimental condition, the removal of CODCr occurred mainly through the indirect oxidation of active chlorine and ·OH, and the removal of NH4+-N mainly through the indirect oxidation of active chlorine.

Improved high shear mixers enhance fast halogenation reactions of alcohols

In the view of green and sustainable synthesis, there is still a broad space for improvement with respect to the halogenations of the alcohol, which is facing up with the problems of high input and low yield. Herein, high shear mixers (HSM) were exploited first to enhance the bromination of tert-butyl alcohol by improving the mixing performance. Notably, the baffle plate (BP) was first proposed to facilitate the in situ separation of the product from the reaction system, promoting the reversible reaction equilibrium to shift toward the right direction. The influences of the molar ratio of reactants, temperature, feed rate, rotor speed, and height of BP were investigated on the reaction performance, which provides a facile and cost-efficient intensified technology to prepare 2-bromo-2-methylpropane. The maximum yield is achieved as 94.8% using HSM, obviously higher than that using CST (82.6%) and HST-Impeller (87.6%), and the reaction time can be shortened by 75%. Furthermore, such HSM and BP-HSM can successfully improve the yields of some fast alcohol halogenations with shorter reaction time. This ingenious exploration of BP in HSM provides valuable guidance on design new technology to intensify some fast organic chemical reactions with the products immiscible to the reactants.

Filling fraction measurement around a drying drop onto nanoporous silicon using digital holographic microscopy

In this work, we implemented an off-axis digital holographic microscopy (DHM) setup to study the behavior of liquid drops on nanostructured porous silicon (PS) membranes. When a liquid comes into contact with the PS structure, capillary action and surface tension give rise to imbibition of the liquid into the intricate volume of the pores. At the same time, the vapor field developed around the drop enhances liquid condensation and evaporation into and from the pores. The complex interplay between these phenomena (capillary driven internal flows, condensation, and evaporation) is not yet fully understood but the methods we propose can provide new insights. We demonstrate how DHM allows determining the filling fraction of the porous membrane around drying drops of water and isobutyl alcohol. The phase information obtained from registered holograms provides quantitative information that permits to reconstruct the filling fraction along the porous membrane and its evolution during the drying process. Additionally, relevant parameters such as speed and contact angle during retraction of the drops can be measured. These methods can be further extended to other porous materials, such as porous alumina, micro- and macro-PS, to develop better fluid-dynamic models for describing fluid behavior in highly confined structures.

Degradation of phenol in wastewater through an integrated dielectric barrier discharge and Fenton/photo-Fenton process

In this study, a non-thermal dielectric barrier discharge-Fenton/photo-Fenton process was investigated to remove phenol from synthetic wastewater. The changes and optimal values of influencing parameters, including treatment time, iron concentration, phenol initial concentration, and pH, were investigated based on the central composite design (CCD) method. The presence of 0.4 mmol/L of iron in the phenol solution with a concentration of 100 mg/L increased the removal efficiency and pseudo-first-order kinetic constant compared to dielectric barrier discharge cold plasma (DBDP) alone from 0.0824 min−1 and 56.8% to 0.2078 min−1 and 86.83%, respectively. The phenol removal efficiency was reduced to 52.9%, 45.6% and 31.8% by adding tert-butyl alcohol (TBA) with concentrations of 50, 100, and 200 mg/l, respectively. After 12 min of DBDP irradiation, the pH of the sample decreased from 5.95 to 3.42, and the temperature of the sample increased from 19.3 to 37.2 degrees Celsius. The chemical oxygen demand (COD) of the sample containing 100 mg/L phenol under plasma-Fenton/photo-Fenton irradiation decreased from 241 mg/L to 161 mg/L. Phenol removal efficiency after 10 min of treatment in the presence of 0.4 mmol/L of iron with the reactor volume of 50 mL was 87%, but the efficiency decreased to 76%, 47%, and 9% by increasing the volume to 100, 200, and 400 mL, respectively. Reducing the power led to a decrease in the removal efficiency from 56.8% for 100 W power to 10.8% for 40 W. The energy efficiency for 50% removal by DBDP and plasma-Fenton/photo-Fenton systems was 5.86×10−3 kWh/mg and 1.27×10−3 kWh/mg, respectively.