Synergetic Bioproduction of Short-Chain Fatty Acids from Waste Activated Sludge Intensified by the Combined Use of Potassium Ferrate and Biosurfactants

The synergetic effect and underlying mechanism of potassium ferrate(PF)with tea saponin(TS,a biosurfactant)in producing short chain fatty acids(SCFAs)from anaerobic fermentation of waste activated sludge(WAS)were explored in this work.Experimental results showed that 0.2 g PF(g TSS)^(-1)(total suspended solid)combined with 0.02 g TS(g TSS)^(-1) could further improve SCFAs’production,and the maximum SCFAs content reached 2008.7 mg COD L^(-1),which is 1.2 and 4.5 times higher than those with PF and TS individually added,respectively,and 5.3 times higher than that of blank WAS on Day 12.In the model substrates experiments,the degradation rates of bovine serum albumin and dextran with combination of PF and TS were 41.3%±0.1% and 48.5%±0.06%,respectively,on Day 3,which are lower than those in blank WAS(with degradation rates of 72.3%±0.5%and 90.3%±0.3%).It was revealed that the oxidative effect of PF and the solubilization of TS caused more organic matters to be dissolved out from WAS,providing a large number of biodegradable substances for subsequent SCFAs production.While WAS pretreated with the combination of PF and TS,the relative abundances of Firmicutes increased from 6.4%(blank)to 38.6%,and that of Proteobacteria decreased from 41.8%(blank)to 21.8%.The combination of PF and TS promoted the hydrolysis process of WAS by enriching Firmicutes,and then increased acetic acid production by inhibiting Proteobacteria that consumed SCFAs.Meanwhile,at the genus level,acidogenesis bacteria(e.g.,Proteiniclasticum and Petrimonas)were enriched whereas SCFAs consuming bacteria(e.g.,Dokdonella)were inhibited.

Flotation behaviors of chalcopyrite and galena using ferrate(Ⅵ) as a depressant

This paper investigated the effects of potassium ferrate(PF)on the flotation performances of chalcopyrite and galena.The flotation results showed that PF obviously depressed galena,but had little effects on the floatability of chalcopyrite within pH range of 4.0–12.0.Zeta potential tests showed that the addition of PF induced the formation of more amounts of hydrophilic species on the surface of galena under an alkaline environment.Industrial grade O-isopropyl-N-ethyl thionocarbamate(IPETC)chemically adsorbed on the surface of the PF-treated chalcopyrite and galena after its addition.Contact angle measurements showed that with the addition of PF,the contact angle of the galena surface significantly decreased compared with the chalcopyrite surface.Localized electrochemical impedance spectroscopy(LEIS)tests showed that the addition of PF increased the impedance of the galena surface.X-ray photoelectron spectroscopy(XPS)analyses revealed that the formation of hydrophilic species,namely lead sulfite,lead hydroxide and ferric hydroxide,on the galena surface,decreased its floatability in the presence of PF,while the formation of hydrophobic species,namely copper disulfide and elemental sulfur,on the chalcopyrite surface,maintained its floatability.Finally,a descriptive model for the reaction of PF with chalcopyrite and galena was proposed.

Effects of Potassium Ferrate and Low-Temperature Thermal Hydrolysis Co-Pretreatment on the Hydrolysis and Anaerobic Digestion Process of Waste Activated Sludge

This study evaluated the effect of potassium ferrate(PF)and low-temperature thermal hydrolysis co-pretreatment on the promotion of sludge hydrolysis process and the impact on acid production in the subsequent anaerobic digestion process.The analytical investigations showed that co-pretreatment significantly facilitated the hydrolysis process of the sludge and contributed to the accumulation of short-chain fatty acids(SCFAs).The pretreatment conditions under the optimal leaching of organic matter from sludge were hydrothermal temperature of 75℃,hydrothermal treatment time of 12 h,and PF dosage of 0.25 g g^(−1)TSS(total suspended solids),according to the results of orthogonal experiments.By pretreatment under proper conditions,the removal rate of soluble chemical oxygen demand(SCOD)achieved 71.8%at the end of fermentation and the removal rate of total phosphorus(TP)was 69.1%.The maximum yield of SCFAs was 750.3 mg L^(−1),7.45 times greater than that of the blank group.Based on the analysis of the anaerobic digestion mechanism,it was indicated that the co-pretreatment could destroy the floc structure on the sludge surface and improve organic matter dissolving,resulting in more soluble organic substances for the acidification process.Furthermore,microbial community research revealed that the main cause of enhanced SCFAs generation was an increase in acidogenic bacteria and a reduction of methanogenic bacteria.

Study on degradation mechanism of aniline solution by potassium ferrate

研究了高铁酸钾投加量、初始pH及苯胺初始浓度对苯胺降解效果的影响。结果表明，苯胺废水的COD去除率照高铁酸钾投加量和苯胺初始浓度的增大而升高，而初始pH对COD去除率影响不明显。对高铁酸钾降解苯胺废水后的产物进行了气相色谱／质谱（GC／MS）分析，在此基础上详细探讨了高铁酸钾降解苯胺的机制。

Oxidative Desulfurization of Model Sulfur Compound by Potassium Ferrate in the Presence of Phosphomolybdic Acid Catalyst

In this work, the removal of thiophene from simulated oil has been studied by using the adsorption, extraction and oxidation/adsorption methods, respectively. In the adsorptive desulfurization process, different commercial adsorbents were used to eliminate thiophene at ambient pressure and mild temperature, and the results showed that carbon powder had the best adsorption ability. In the extractive desulfurization process, the best desulfurization result was obtained when DMF is used. In the oxidative/adsorptive desulfurization procedure using synthesized potassium ferrate as the oxidant and phosphomolybdic acid solution as the catalyst, thiophene was oxidized and removed from hydrocarbons in combination with active carbon adsorption, and the residual sulfur content of simulated oil could be reduced to 15.3mg/L from the original level of 200mg/L, with the desulfurization rate reaching 92.3%.

Treatment of Phenol-Contaminated Soil by Potassium Ferrate Based on pH Control

This study aims to optimize the treatment of phenol-contaminated soil by potassium ferrate. Variations in pH value can accurately reflect the state and reaction status of the entire treatment process. Therefore, the pH value could be an important variable for optimizing the reaction conditions and achieving the automatic control of the process. About 99.89% of phenol was removed after 10 min of the pH-controlled reaction at a rotational speed of 40―70 r/min, with the initial phenol concentration equating to 10.0 g/kg and the total water consumption reaching 2.72 L(at a soil/water ratio of 1:0.68). The test results could provide a basis for practical application of automatic reaction control by pH value.

Effects of operating conditions on iron(hydr)oxides evolution and ciprofloxacin degradation in potassium ferrate-ozone stepwise oxidation system

In this study,a stepwise oxidation system of potassium ferrate(K_(2)FeO_(4))combined with ozone(O+3)was used to degrade ciprofloxacin(CIP).The effects of pH and pre-oxidation time of K_(2)FeO_(4) on the evolution of K_(2)FeO_(4) reduction products(iron(hydr)oxides)and CIP degradation were investigated.It was found that in addition to its own oxidation capacity,K_(2)FeO_(4) can also influence the treatment effect of CIP by changing the catalyst content.The presence of iron(hydr)oxides effectively enhanced the mineralization rate of CIP by catalyzing ozonation.The pH value can influence the content and types of the components with catalytic ozonation effect in iron(hydr)oxides.The K_(2)FeO_(4) pre-oxidation stage can produce more iron(hydr)oxides with catalytic components for subsequent ozonation,but the evolution of iron(hydr)oxides components was influenced by O_(3) treatment.It can also avoid the waste of oxidation capacity owing to the oxidation of iron(hydr)oxides by O_(3) and free radicals.The intermediate degradation products were identified by Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR-MS).Besides,the degradation pathways were proposed.Among the degradation products of CIP,the product with broken quinolone ring structure only appeared in the stepwise oxidation system.

Versatile Functionalization of Carbon Nanomaterials by Ferrate(Ⅵ)

As a high-valent iron compound with Fe in the highest accessible oxidation state,ferrate(VI)brings unique opportunities for a number of areas where chemical oxidation is essential.Recently,it is emerging as a novel oxidizing agent for materials chemistry,especially for the oxidation of carbon materials.However,the reported reactivity in liquid phase(H2SO4 medium)is confusing,which ranges from aggressive to moderate,and even incompetent.Meanwhile,the solid-state reactivity underlying the“dry”chemistry of ferrate(VI)remains poorly understood.Herein,we scrutinize the reactivity of K2FeO4 using fullerene C60 and various nanocarbons as substrates.The results unravel a modest reactivity in liquid phase that only oxidizes the active defects on carbon surface and a powerful oxidizing ability in solid state that can open the inert C=C bonds in carbon lattice.We also discuss respective benefit and limitation of the wet and dry approaches.Our work provides a rational understanding on the oxidizing ability of ferrate(VI)and can guide its application in functionalization/transformation of carbons and also other kinds of materials.

高铁酸钾-过硫酸钠降解萘的效能及机理研究

为了绿色且高效地治理多环芳烃萘污染地下水,采用高铁酸钾-过硫酸钠体系降解萘,考察高铁酸钾和过硫酸钠的摩尔比、pH值和温度对萘降解效果的影响,并探究反应动力学和降解机理。研究显示,当温度为25℃,pH值为5.0,高铁酸钾和过硫酸钠的摩尔比为1∶2时,在50 min时萘最佳降解率为82.3%。采用一级反应动力学方程对萘的降解曲线进行拟合,发现其反应速率k为0.0302 min^(-1),远高于高铁酸钾体系的0.0074 min^(-1)和过硫酸钠体系的0.0034 min^(-1)的总和,表明高铁酸钾-过硫酸钠体系存在协同作用。通过对高铁酸钾-过硫酸钠体系中Fe(Ⅱ)和Fe(Ⅲ)质量浓度变化测定,显示该体系可以活化过硫酸钠且Fe(Ⅱ)和Fe(Ⅲ)质量浓度变化与萘的降解试验结果吻合。采用自由基猝灭试验和电子顺磁共振(Electron Paramagnetic Resonance,EPR)技术探究高铁酸钾-过硫酸钠体系中的活性氧化物种,发现羟基自由基(·OH)和硫酸根自由基(·SO_(4)^(-))都参与了萘的降解过程。采用气相色谱-质谱联用仪(Gas Chromatography and Mass Spectrometry,GC-MS)分析确定了3种萘的中间产物,并提出了一种可能的降解途径。研究发现,萘在降解过程中可被转化为低毒或无毒物质,表明高铁酸钾-过硫酸钠体系对萘的降解是一个渐进降低毒性的过程,可以有效降低环境风险。总之,高铁酸钾-过硫酸钠联合体系作为一种高效的清洁技术,可为治理多环芳烃萘污染地下水提供一定的理论指导。

高铁酸盐体系中高价铁氧中间体对双酚A的降解研究

以典型内分泌干扰物双酚A(BPA)为目标污染物,研究了高铁酸钾[Fe(Ⅵ)]对其的去除效果及机理。通过高效液相色谱仪、离子色谱仪等手段考察了pH、Fe(Ⅵ)投加量和共存离子等因素对BPA去除效果的影响。结果表明,在pH为8.0、Fe(Ⅵ)与BPA浓度比为30∶1时,反应10 min后BPA的降解率达到81.5%。Cl^(-)、SO_4^(2-)、NO^(-)_(3)、HCO^(-)_(3)等共存阴离子未影响Fe(Ⅵ)体系的氧化能力,但Ca^(2+)和Mg^(2+)因加速了Fe(Ⅵ)自分解而抑制了BPA降解。通过淬灭实验对体系中的活性氧物种进行识别,Fe(Ⅵ)及其高价铁氧中间体Fe(Ⅴ)/Fe(Ⅳ)在氧化BPA中起主导作用。在实际水体(自来水、市政二级出水和地下水)中,Fe(Ⅵ)氧化体系对BPA的降解未受到明显影响,证实其具有较高的环境适应性。

电解法制备高铁酸钾及对Sb(Ⅲ)去除效能的研究

实验采用电解法制备高铁酸钾固体,采用XRD、SEM及分光光度法进行表征和纯度分析,证明了纯度可达90%以上。采用K2FeO4对水体中Sb(Ⅲ)进行降解去除,实验表明,在溶液pH=5,Sb(Ⅲ)初始浓度为2?mg/L时,投加K2FeO4为50?mg/L为最优投加量。通过K2FeO4及分解产物在不同pH值下对Sb(Ⅲ)、Sb(Ⅴ)去除实验,发现K2FeO4主要通过分解产物即絮凝、吸附作用对Sb(Ⅲ)去除,去除率在90%以上,且受pH值影响小。通过K2FeO4除Sb(Ⅲ)沉淀物的XPS、FTIR表征分析,证明了Sb(Ⅲ)可以有效的被K2FeO4去除。

催化动力学体系褪色光度法测定痕量Cr(VI)

基于在硫酸介质中,微量Cr(VI)能显著催化KBrO4氧化罗丹明B褪色。建立了测定痕量Cr(VI)新的分析方法,线性范围是0.02～2.0μg/ml,具有高选择性,高灵敏度,摩尔吸光系数为1.3×105L.mol-1.cm-1,应用于废水及环境水中的Cr(VI)的测定,结果令人满意。

高铁酸盐及其联用工艺在水处理中应用综述

综述了高铁酸钾的相关特性以及其在水处理应用中的研究现状,并对其在应用中所展现的优缺点进行解析,重点介绍为克服高铁酸钾单独应用中所出现的缺陷,高铁酸钾与其他技术联用的研究进展。分析了各种高铁酸钾联用技术对于水中污染物的降解原理,并对于国内外水中污染物的研究报道进行了系统的梳理,最后对高铁酸钾联用技术在未来水环境治理中的发展进行展望。

基于RBF神经网络模型对污泥减量优化的研究

研究了温度、pH值、反应时间、高铁酸钾投加量等因素对污泥溶胞效果和分解效果的影响,并通过建立RBF神经网络模型对实验进行优化。研究结果表明,温度为60℃、反应时间为2~4 h、pH值为12、高铁酸钾投加量5.5mg/(gSS)的条件下,污泥减量处理效果显著且较为经济。此外,RBF神经网络模型计算的污泥溶胞率、污泥分解率值与实验得出的结果,两者相对误差均小于5%,验证了该模型的良好拟合性。

中药复方VIS抑制急性高眼压大鼠视网膜神经节细胞凋亡机制

目的研究中药复方VIS的不同配比对急性高眼压大鼠视网膜凋亡相关蛋白Bcl-2／Bax表达的影响，以及最佳配比复方VIS对视网膜神经节细胞外向钾电流的调控，探讨其视神经保护的可能机制。方法利用前房灌注生理盐水的方法急性升高大鼠眼内压，接着使用不同配比的VIS及LBP、DSX、阳性对照药物灌胃7d，利用免疫组化方法检测凋亡相关基因的表达。接着选取最佳配比的复方VIS，采用全细胞膜片钳技术观察其对急性高眼压大鼠RGC的电压门控外向钾电流的影响。将细胞膜电位钳制在-70mV，然后给予一系列400ms的去极化脉冲，以10mV的递增使细胞去极化到＋20mV，从而诱导出外向钾电流。结果前房急性灌注生理盐水7d造成视网膜凋亡相关基因Bcl-2／Bax比值的下调，不同配比的VIS呈不同程度地下调促凋亡基因Bax，促进凋亡抑制基因Bcl-2的表达，因而提高Bcl-2／Bax比值；复方VIS8具有抑制或降低急性高眼压损伤后RGC的外向钾电流的电流幅度下调的作用。结论急性眼内压升高引起视网膜内在凋亡途径的启动，中药复方VIS能够有效地抑制神经节细胞的凋亡，其中VIS8作用显著，且具有抑制或降低急性高眼压损伤后RGC的外向钾电流幅度下调的作用。这可能是中药复方VIS抑制急性高眼压RGC凋亡，从而保护视神经及RGC的机制之一。

中药复方VIS抑制急性高眼压大鼠视网膜神经节细胞凋亡

目的研究中药复方VIS的不同配比对急性高眼压大鼠视网膜凋亡相关分子Bcl-2／Bax表达的影响，以及其组成成分DSX对视网膜神经节细胞外向钾电流的调控，探讨其视神经保护的可能机制。方法利用前房灌注生理盐水的方法急性升高大鼠眼内压，接着使用不同配比比例的VIS及LG、DSX灌胃7d，利用免疫组化方法检测凋亡相关基因的表达，再选取其组成成分DSX利用全细胞膜片钳技术观察其对急性分离的正常大鼠视网膜神经节细胞的电压门控外向钾电流的作用。将细胞膜电位钳制在-70mV，然后给予一系列400ms的去极化脉冲，以10mV的递增使细胞去极化到＋20mV，从而诱导出外向钾电流。结果前房急性灌注生理盐水7d造成视网膜凋亡相关基因Bcl-2／Bax比值的下调，不同配比的VIS呈不同程度地下调促凋亡基因Bax，促进凋亡抑制基因Bcl-2的表达，因而提高Bcl-2／Bax比值。同时胞外施加的DSX对大鼠RGC的外向钾电流的电流幅度呈电压依赖性压抑。结论急性眼内压升高引起视网膜内在凋亡途径的启动，中药复方VIS能够有效地抑制神经节细胞的凋亡，其组成成分DSX可逆地压抑大鼠视网膜神经节细胞外向钾电流，这可能是灯盏细辛对高眼压引起的视野丢失、视网膜神经节细胞损伤保护作用的机制之一。

Developed New Procedure for Low Concentrations of Hydrazine Determination by Spectrophotometry: Hydrazine-Potassium Permanganate System

An indirect, sensitive and accurate method for the determination of trace amounts of hydrazine is described. In this proposed the spectrophotometric method is based on its reduction properties of hydrazine with a known concentration of potassium permanganate to reduce the colour. The absorbance of unreduced permanganate is measured the colour difference at different wavelengths 546 and 526 nm which show an absorption spectrum with hydrazine. Hydrazine can be determined in the range of 100 - 700 μg/ml with correlation coefficient of 0.999 and relative standard deviation 1%. The method is successfully applied for the determination of hydrazine in water streams in nuclear reactors/purex process/boiler water and polluted water samples.

高铁酸钾降解隧道施工废水中苯酚的效能研究

采用高铁酸钾对两种隧道施工废水中的苯酚、COD、氨氮(NH3-N)进行去除,并分别研究高铁酸钾浓度、温度、pH、时间和苯酚浓度对苯酚去除效果的影响。采用纳氏比色法、分光光度法、高效液相色谱法对废水中的NH3-N、COD、苯酚浓度进行测定;通过设计砂柱实验,模拟真实的地下水环境系统下处理苯酚污染的地下水。结果表明:高铁酸钾去除含苯酚的隧道施工废水效果较好;施工废水中的苯酚降解随高铁酸钾的投加量增加而增加、随温度的升高而降低;施工废水中的苯酚降解在酸性条件下效果较好,随着pH的增加效果降低;同时,高铁酸钾对含苯酚的隧道施工废水中的COD、氨氮(NH3-N)去除也有一定效果。通过淬灭实验探究反应当中的产生的自由基类别。

醋酸钠和次氯酸钠对高铁酸钾溶液稳定性的影响

基于分光光度法研究了醋酸钠和次氯酸钠对高铁酸钾溶液稳定性的影响。对于1 mmol/L的高铁酸钾溶液,在25℃和pH值12的环境中,醋酸钠能提高其稳定性,当醋酸钠浓度达到10 mmol/L时,高铁酸钾的稳定性最好,静置10 h高铁酸钾的留存率约79%;为验证醋酸钠在高铁酸钾分解有机物的反应中是否仍具有稳定高铁酸钾的作用,以降解苯酚为例,当醋酸钠与高铁酸钾摩尔比为51时,苯酚的降解率达到最高值88.9%。次氯酸钠对高铁酸钾的稳定性影响实验结果显示,次氯酸钠可以提高高铁酸钾稳定性,次氯酸钠耗尽前,高铁酸钾留存率接近100%。