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Two-dimensional self-assembly of melem and melemium cations at pH-controlled aqueous solution–Au(111)

Shinobu Uemura,Kenki Sakata,Masashi Aono,Yusuke Nakamura,Masashi Kunitake

《化学科学与工程前沿（英文）》 2016年 第10卷 第2期   页码 294-300 doi: 10.1007/s11705-016-1564-4

摘要： Two-dimensional self-assembly of melem at pH-controlled aqueous solution-Au(111) interfaces has been investigated by electrochemical scanning tunneling microscopy. In the solutions with pH>p of melem, two ordered self-assembled structures (honeycomb and close-packed structures) and one disordered fibrillar structure were observed as a function of the surface coverage of melem controlled by the electrode potential. In contrast, in the acidic solution with pH

关键词： self-assembly     scanning tunneling microscopy     electrochemistry     structural phase transition     melem    

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Removing ammonia from air with a constant pH, slightly acidic water　spray wet scrubber using recycled

Ahmad Kalbasi Ashtari, Amir M. Samani Majd, Gerald L. Riskowski, Saqib Mukhtar, Lingying Zhao

《环境科学与工程前沿（英文）》 2016年 第10卷 第6期 doi: 10.1007/s11783-016-0869-3

摘要： Slightly acidic solutions are a practical means of removing ammonia from air Scrubbed NH accumulates in solution as NH and should be an excellent fertilizer Increased air velocity decreased NH removal and increased NH collection Previous research on wet scrubbers has only studied highly acidic scrubbing solutions because of their high ammonia capture efficiencies; however, the high acidity created practical problems. Lower acidity solutions would reduce corrosion, maintenance, and cost; however, designers may need to use strategies for increasing scrubber effectiveness, such as using lower air velocities. The objective of this study was to determine if a spray scrubber with slightly acidic and higher pH scrubbing solution (pH from 2 to 8) could effectively remove NH from NH laden air (such as animal building exhaust air), and also collect this valuable resource for later use as a fertilizer. A bench-scale spray wet scrubber treated 20 ppmv NH /air mixture in a countercurrent contact chamber. First, the solution pH was varied from 2 to 8 while maintaining constant air velocity at 1.3 m·s . Next, air velocity was increased (2 and 3 m·s ) while solution pH remained constant at pH6. At 1.3 m·s , NH removal efficiencies ranged between 49.0% (pH8) and 84.3% (pH2). This study has shown that slightly acidic scrubbing solutions are a practical means of removing ammonia from air especially if the scrubber is designed to increase collisions between solution droplets and NH molecules. The NH removed from the air was held in solution as NH and accumulates over time so the solution should be an excellent fertilizer.

关键词： Ammonia     Spray wet scrubber     Slightly acidic scrubbing solution     Controlled pH     Removal efficiency    

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Carbon dots-based fluorescence sensor for two-photon imaging of pH in diabetic mice

《化学科学与工程前沿（英文）》 2023年 第17卷 第3期   页码 298-306 doi: 10.1007/s11705-022-2212-9

摘要： Herein, a reversible pH fluorescent sensor was developed using caffeic acid as the precursor by one-step solvothermal synthesis method. The carbon dots-based sensor (CA-CDs) exhibited pH-dependent increase in fluorescence intensity and showed linear relationship in the range of pH 6.60 and 8.00. Notably, the fluorescence sensor has a reversible response to pH change. Finally, the CA-CDs has been successfully applied for two-photon imaging of the pH in liver and kidney of diabetic mice. Imaging results showed that the pH value in kidney of diabetic mice was lower than that of the normal mice, while the pH value in liver of diabetic mice was almost the same as that of the normal mice. The present study provides a simple analytical method for pH detection suitable for in vivo.

关键词： carbon dots     two-photon imaging     pH     diabetic mice    

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Sorption of tetracycline to sediments and soils: assessing the roles of pH, the presence of cadmium and

Guixiang ZHANG, Xitao LIU, Ke SUN, Ye ZHAO, Chunye LIN

《环境科学与工程前沿（英文）》 2010年 第4卷 第4期   页码 421-429 doi: 10.1007/s11783-010-0265-3

摘要： Batch sorption experiments were conducted to evaluate the sorption behavior of tetracycline (TC, H L) on sediments and soils in the presence and absence of cadmium (Cd), as affected by pH and properties of sediments and soils. The results indicated stronger nonlinearity and higher capacity of TC sorption on sediments than on soils. Sorption of TC also strongly depended on environmental factors and sediment/soil properties. Lower pH facilitated TC sorption through a cation exchange mechanism, which also took place at pH values above 5.5, where TC existed as a zwitterion (H L ) or anions (HL and L ). When pH was above 7, however, ligand-promoted dissolution of TC might occur due to TC weakening the Al-O bond of aluminum oxide and the Fe-O bond of iron oxide. Natural organic matter (NOM) plays a more important role in TC sorption than cation exchange capacity (CEC) and clay contents. The presence of Cd (II) increased TC sorption on both sediments and soils, which resulted from the decrease of equilibrium solution pH caused by Cd exchange with H ions of sediment/soil surfaces. The increase of TC sorption was also related to the formation of TC-Cd complexes, where Cd acted as a bridge between the sediment/soil and TC.

关键词： sorption     tetracycline (TC)     pH     cadmium (Cd)     antibiotic    

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Effect of pH on biologic degradation of

Hongjing LI, Mengli HAO, Jingxian LIU, Chen CHEN, Zhengqiu FAN, Xiangrong WANG

《环境科学与工程前沿（英文）》 2012年 第6卷 第2期   页码 224-230 doi: 10.1007/s11783-011-0314-6

摘要： In this paper, the effect of pH on biological degradation of by alga-lysing bacteria in laboratory-scale sequencing batch biofilm reactors (SBBRs) was investigated. After 10 d filming with waste activated sludge, the biological film could be formed, and the bioreactors in which laid polyolefin resin filler were used to treat algal culture. By comparing the removal efficiency of chlorophyll at different aerobic time, the optimum time was determined as 5 h. Under pH 6.5, 7.5, and 8.5 conditions, the removal rates of were respectively 75.9%, 83.6%, and 78.3% (in term of chlorophyll ), and that of Chemical Oxygen Demand (COD ) were 30.6%, 35.8%, and 33.5%. While the removal efficiencies of ammonia nitrogen ( ) were all 100%. It was observed that the sequence of the removal efficiencies of algae, and organic matter were pH 7.5>pH 8.5>pH 6.5. The results showed that the dominant alga-lysing bacteria in the SBBRs was strain HM-01, which was identified as sp. by Polymerase Chain Reaction (PCR) amplification of the 16S rRNA gene, Basic Local Alignment Search Tool (BLAST) analysis, and comparison with sequences in the GenBank nucleotide database. The algicidal activated substance which HM-01 strain excreted could withstand high temperature and pressure, also had better hydrophily and stronger polarity.

关键词： pH     biological degradation     alga-lysing bacteria     sequencing batch biofilm reactor (SBBR)     16S rRNA     Bacillus sp    

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Synthesis and characterization of biocompatible polyurethanes for controlled release of hydrophobic and

Juichen YANG,Hong CHEN,Yuan YUAN,Debanjan SARKAR,Jie ZHENG

《化学科学与工程前沿（英文）》 2014年 第8卷 第4期   页码 498-510 doi: 10.1007/s11705-014-1451-9

摘要： Design of biocompatible and biodegradable polymer systems for sustained and controlled release of bioactive agents is critical for numerous biomedical applications. Here, we designed, synthesized, and characterized four polyurethane carrier systems for controlled release of model drugs. These polyurethanes are biocompatible and biodegradable because they consist of biocompatible poly(ethylene glycol) or poly(caprolactone diol) as soft segment, linear aliphatic hexamethylene diisocyanate or symmetrical aliphatic cyclic dicyclohexylmethane-4,4′-diisocyanate as hard segment, and biodegradable urethane linkage. They were characterized with Fourier transform infrared spectroscopy, atomic force microscope, and differential scanning calorimetry, whereas their degradation behaviors were investigated in both phosphate buffered saline and enzymatic solutions. By tuning polyurethane segments, different release profiles of hydrophobic and hydrophilic drugs were obtained in the absence and presence of enzymes. Such difference in release profiles was attributed to a complex interplay among structure, hydrophobicity, and degradability of polyurethanes, the size and hydrophobicity of drugs, and drug-polymer interactions. Different drug-polyurethane combinations modulated the distribution and location of the drugs in polymer matrix, thus inducing different drug release mechanisms. Our results highlight an important role of segmental structure of the polyurethane as an engineering tool to control drug release.

关键词： phase structure     degradation     polyurethanes     controlled release     drug delivery    

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A Cu-modified active carbon fiber significantly promoted HS and PH simultaneous removal at a low reaction

《环境科学与工程前沿（英文）》 2021年 第15卷 第6期 doi: 10.1007/s11783-021-1425-3

摘要：

• Cu0.15-ACF performs the best for H2S and PH3 simultaneous removal.

关键词： ACF     H2S     PH3     Cu     Low temperature     Simultaneous removal    

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Decomposition of perfluorooctanoic acid by microwave-activated persulfate: Effects of temperature, pH

Yuchi LEE, Shanglien LO, Jeff KUO, Chinghong HSIEH

《环境科学与工程前沿（英文）》 2012年 第6卷 第1期   页码 17-25 doi: 10.1007/s11783-011-0371-x

摘要： Microwave-hydrothermal treatment of persistent and bioaccumulative perfluorooctanoic acid (PFOA) in water with persulfate ( ) has been found effective. However, applications of this process to effectively remediate PFOA pollution require a better understanding on free-radical scavenging reactions that also take place. The objectives of this study were to investigate the effects of pH (pH= 2.5, 6.6, 8.8, and 10.5), chloride concentrations (0.01–0.15 mol·L ), and temperature (60°C, 90°C, and 130°C) on persulfate oxidation of PFOA under microwave irradiation. Maximum PFOA degradation occurred at pH 2.5, while little or no degradation at pH 10.5. Lowering system pH resulted in an increase in PFOA degradation rate. Both high pH and chloride concentrations would result in more scavenging of sulfate free radicals and slow down PFOA degradation. When chloride concentrations were less than 0.04 mol·L at 90°C and 0.06 mol·L at 60°C, presence of chloride ions had insignificant impacts on PFOA degradation. However, beyond these concentration levels, PFOA degradation rates reduced significantly with an increase in chloride concentrations, especially under the higher temperature.

关键词： microwave     perfluorooctanoic acid     pH     persulfate     chloride ions     perfluorocarboxylic acids    

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Co-fermentation of waste activated sludge with food waste for short-chain fatty acids production: effect of pH

Leiyu FENG, Yuanyuan YAN, Yinguang CHEN

《环境科学与工程前沿（英文）》 2011年 第5卷 第4期   页码 623-632 doi: 10.1007/s11783-011-0334-2

摘要： Effect of pH ranging from 4.0 to 11.0 on co-fermentation of waste activated sludge (WAS) with food waste for short-chain fatty acids (SCFAs) production at ambient temperature was investigated in this study. Experimental results showed that the addition of food waste significantly improved the performance of WAS fermentation system, which resulted in the increases of SCFAs production and substrate reduction. The SCFAs production at pH 6.0, 7.0, 8.0, and 9.0 and fermentation time of 4 d was respectively 5022.7, 6540.5, 8236.6, and 7911.7 mg COD·L , whereas in the blank tests (no pH adjustment, pH 8.0 (blank test 1), no food waste addition, pH 8.0 (blank test 2), and no WAS addition (blank test 3)) it was only 1006.9, 971.1, and 1468.5 mg COD·L , respectively. The composition of SCFAs at pH from 6.0 to 9.0 was also different from other conditions and propionic acid was the most prevalent SCFA, which was followed by acetic and n-butyric acids, while acetic acid was the top product under other conditions. At pH 8.0 a higher volatile suspended solids (VSS) reduction of 16.6% for the mixture of WAS and food waste than the sole WAS indicated a synergistic effect existing in fermentation system with WAS and food waste. The influence of pH on the variations of nutrient content was also studied during anaerobic fermentation of the mixture of WAS and food waste at different pH conditions. The release of increased with fermentation time at all pH values investigated except 4.0, 5.0 and in blank test one. The concentrations of soluble phosphorus at acidic pHs and in the blank test one were higher than those obtained at alkaline pHs. Ammonia and phosphorus need to be removed before the SCFAs-enriched fermentation liquid from WAS and food waste was used as the carbon source.

关键词： waste activated sludge (WAS)     food waste     co-fermentation     short-chain fatty acids (SCFAs)     pH     synergistic effect    

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Tuning the electronic structure of NiCoP arrays through V doping for pH-universal hydrogen evolution

Yu Lin, Jinlei Wang, Duanlin Cao, Yaqiong Gong

《化学科学与工程前沿（英文）》 2021年 第15卷 第5期   页码 1134-1146 doi: 10.1007/s11705-020-2014-x

摘要： The exploration of cost-effective, high-performance, and stable electrocatalysts for the hydrogen evolution reaction (HER) over wide pH range (0–14) is of paramount importance for future renewable energy conversion technologies. Regulation of electronic structure through doping vanadium atoms is a feasible construction strategy to enhance catalytic activities, electron transfer capability, and stability of the HER electrode. Herein, V-doped NiCoP nanosheets on carbon fiber paper (CFP) (denoted as V -NiCoP/CFP) were constructed by doping V modulation on NiCoP nanosheets on CFP and used for pH-universal HER. Benefiting from the abundant catalytic sites and optimized hydrogen binding thermodynamics, the resultant V -NiCoP/CFP demonstrates a significantly improved HER catalytic activity, requiring overpotentials of 46.5, 52.4, and 85.3 mV to reach a current density of 10 mA·cm in 1 mol·L KOH, 0.5 mol·L H SO , and 1 mol·L phosphate buffer solution (PBS) electrolytes, respectively. This proposed cation-doping strategy provides a new inspiration to rationally enhance or design new-type nonprecious metal-based, highly efficient, and pH-universal electrocatalysts for various energy conversion systems.

关键词： hydrogen evolution reaction     transition metal phosphides     pH-universal     vanadium doping     carbon fiber paper    

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Acid resistance of methanogenic bacteria in a two-stage anaerobic process treating high concentration methanol wastewater

ZHOU Xuefei, REN Nanqi

《环境科学与工程前沿（英文）》 2007年 第1卷 第1期   页码 53-56 doi: 10.1007/s11783-007-0010-8

摘要： In this study, the two-stage upflow anaerobic sludge blanket (UASB) system and batch experiments were employed to evaluate the performance of anaerobic digestion for the treatment of high concentration methanol wastewater. The acid resistance of granular sludge and methanogenic bacteria and their metabolizing activity were investigated. The results show that the pH of the first UASB changed from 4.9 to 5.8 and 5.5 to 6.2 for the second reactor. Apparently, these were not the advisable pH levels that common methanogenic bacteria could accept. The methanogenic bacteria of the system, viz. Methanosarcina barkeri, had some acid resistance and could still degrade methanol at pH 5.0. If the methanogenic bacteria were trained further, their acid resistance would be improved somewhat. Granular sludge of the system could protect the methanogenic bacteria within its body against the impact of the acidic environment and make them degrade methanol at pH 4.5. The performance of granular sludge was attributed to its structure, bacteria species, and the distribution of bacterium inside the granule.

关键词： pH     Granular     upflow anaerobic     advisable pH     methanogenic    

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Aptamer-coded DNA nanoparticles for targeted doxorubicin delivery using pH-sensitive spacer

Pengwei Zhang, Junxiao Ye, Ergang Liu, Lu Sun, Jiacheng Zhang, Seung Jin Lee, Junbo Gong, Huining He, Victor C. Yang

《化学科学与工程前沿（英文）》 2017年 第11卷 第4期   页码 529-536 doi: 10.1007/s11705-017-1645-z

摘要： An anticancer drug delivery system consisting of DNA nanoparticles synthesized by rolling circle amplification (RCA) was developed for prostate cancer membrane antigen (PSMA) targeted cancer therapy. The template of RCA was a DNA oligodeoxynucleotide coded with PSMA-targeted aptamer, drug-loading domain, primer binding site and pH-sensitive spacer. Anticancer drug doxorubicin, as the model drug, was loaded into the drug-loading domain (multiple GC-pair sequences) of the DNA nanoparticles by intercalation. Due to the integrated pH-sensitive spacers in the nanoparticles, in an acidic environment, the cumulative release of doxorubicin was far more than the cumulative release of the drug in the normal physiological environment. In cell uptake experiments, treated with doxorubicin loaded DNA nanoparticles, PSMA-positive C4-2 cells could take up more doxorubicin than PSMA-null PC-3 cells. The prepared DNA nanoparticles showed the potential as drug delivery system for PSMA targeting prostate cancer therapy.

关键词： aptamer     DNA nanoparticles     rolling circle amplification     doxorubicin     drug delivery     pH sensitive    

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Size-controlled green synthesis of silver nanoparticles assisted by L-cysteine

Wenchao Zhang,Lin Zhang,Yan Sun

《化学科学与工程前沿（英文）》 2015年 第9卷 第4期   页码 494-500 doi: 10.1007/s11705-015-1527-1

摘要： A green and size-controlled synthesis of silver nanoparticles (Ag NPs) in aqueous solution with the assistance of L-cysteine is presented. The size of Ag NPs decreases with the increase of L-cysteine concentration, and thus can be controlled by adjusting L-cysteine concentration. TEM analysis shows that Ag NPs with an average size of 3 nm can be produced in the presence of 1.0 mmol/L L-cysteine, about one sixth of the size of Ag NPs obtained in the absence of L-cysteine (17 nm). The as-synthesized silver colloidal solution is stable and can be stored at room temperature for at least two months without any precipitation. This L-cysteine assisted method is simple, feasible and efficient, and would facilitate the production and application of Ag NPs.

关键词： nanoparticles     silver     L-cysteine     size distribution     synthesis    

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Analysis and stabilization control of a voltage source controlled wind farm under weak grid conditions

《能源前沿（英文）》 2022年 第16卷 第6期   页码 943-955 doi: 10.1007/s11708-021-0793-5

摘要： This paper investigates and discusses the interaction stability issues of a wind farm with weak grid connections, where the wind turbines (WTs) are controlled by a new type of converter control strategy referred to as the voltage source (VS) control. The primary intention of the VS control method is to achieve the high-quality inertial response capability of a single WT. However, when it is applied to multiple WTs within a wind farm, its weak-grid performance regarding the stability remains concealed and needs to be clarified. To this end, a frequency domain model of the wind farm under the VS control is first developed. Based on this model and the application of a stability margin quantification index, not only the interactions between the wind farm and the weak grid but also those among WTs will be systematically assessed in this paper. A crucial finding is that the inertial response of VS control has negative impacts on the stability margin of the system, and the dominant instability mode is more related to the interactions among the WTs rather than the typical grid-wind farm interaction. Based on this knowledge, a stabilization control strategy is then proposed, aiming for stability improvements of VS control while fulfilling the demand of inertial responses. Finally, all the results are verified by time-domain simulations in power systems computer aided design/electromagnetic transients including DC(PSCAD/EMTDC).

关键词： weak grids     voltage source (VS) control     wind turbine (WT)     stabilization control     wind farm     inertial response    

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Efficient dechlorination of 2,4-dichlorophenol in an aqueous media with a mild pH using a Pd/TiO

Jiangkun DU,Jianguo BAO,Wei HU

《环境科学与工程前沿（英文）》 2015年 第9卷 第5期   页码 919-928 doi: 10.1007/s11783-015-0794-x

摘要： In this study, palladium-loaded titania nanotubes was fabricated on a titanium plate (Pd/TiO NTs/Ti) for efficient electrodechlorination of 2,4-chlorophenol with a mild pH condition. The nature of Pd/TiO NTs/Ti electrodes was characterized by field-emission scanning electron microscope (FESEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV) techniques. The characterization results indicated the generation of Pd nanoparticles which were evenly dispersed on titania nanotubes arrays on the Pd/TiO NTs/Ti surface. An effective degradation efficiency of up to 91% was achieved within 60 min at cathode potential of −0.7 V ( SCE) and initial pH of 5.5. The effects of the applied cathode potential and initial pH on the degradation efficiency were studied. A near neutral condition was more favorable since very low and very high pHs were not conducive to the dechlorination process. Furthermore, the intermediates analysis showed that the Pd/TiO NTs/Ti electrode could completely remove chlorine from 2, 4-dichlorophenol since only phenol was detected as the byproduct and the concentration of released chlorine ions indicated near-complete dechlorination. This work presents a good alternative technique for eliminating persistent chlorophenols in polluted wastewater without maintaining strong acidic environment.

关键词： Pd/TiO2NTs/Ti cathode     chlorophenols     electrocatalytic dechlorination     wastewater treatment    

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标题 作者 时间 类型 操作

Two-dimensional self-assembly of melem and melemium cations at pH-controlled aqueous solution–Au(111)

Shinobu Uemura,Kenki Sakata,Masashi Aono,Yusuke Nakamura,Masashi Kunitake

期刊论文

Removing ammonia from air with a constant pH, slightly acidic water　spray wet scrubber using recycled

Ahmad Kalbasi Ashtari, Amir M. Samani Majd, Gerald L. Riskowski, Saqib Mukhtar, Lingying Zhao

期刊论文

Carbon dots-based fluorescence sensor for two-photon imaging of pH in diabetic mice

期刊论文

Sorption of tetracycline to sediments and soils: assessing the roles of pH, the presence of cadmium and

Guixiang ZHANG, Xitao LIU, Ke SUN, Ye ZHAO, Chunye LIN

期刊论文

Effect of pH on biologic degradation of

Hongjing LI, Mengli HAO, Jingxian LIU, Chen CHEN, Zhengqiu FAN, Xiangrong WANG

期刊论文

Synthesis and characterization of biocompatible polyurethanes for controlled release of hydrophobic and

Juichen YANG,Hong CHEN,Yuan YUAN,Debanjan SARKAR,Jie ZHENG

期刊论文

A Cu-modified active carbon fiber significantly promoted HS and PH simultaneous removal at a low reaction

期刊论文

Decomposition of perfluorooctanoic acid by microwave-activated persulfate: Effects of temperature, pH

Yuchi LEE, Shanglien LO, Jeff KUO, Chinghong HSIEH

期刊论文

Co-fermentation of waste activated sludge with food waste for short-chain fatty acids production: effect of pH

Leiyu FENG, Yuanyuan YAN, Yinguang CHEN

期刊论文

Tuning the electronic structure of NiCoP arrays through V doping for pH-universal hydrogen evolution

Yu Lin, Jinlei Wang, Duanlin Cao, Yaqiong Gong

期刊论文

Acid resistance of methanogenic bacteria in a two-stage anaerobic process treating high concentration methanol wastewater

ZHOU Xuefei, REN Nanqi

期刊论文

Aptamer-coded DNA nanoparticles for targeted doxorubicin delivery using pH-sensitive spacer

Pengwei Zhang, Junxiao Ye, Ergang Liu, Lu Sun, Jiacheng Zhang, Seung Jin Lee, Junbo Gong, Huining He, Victor C. Yang

期刊论文

Size-controlled green synthesis of silver nanoparticles assisted by L-cysteine

Wenchao Zhang,Lin Zhang,Yan Sun

期刊论文

Analysis and stabilization control of a voltage source controlled wind farm under weak grid conditions

期刊论文

Efficient dechlorination of 2,4-dichlorophenol in an aqueous media with a mild pH using a Pd/TiO

Jiangkun DU,Jianguo BAO,Wei HU

期刊论文