CANADIAN JOURNAL OF CHEMICAL ENGINEERING
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2020
·Vol. 99
·期 2
·458-466
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IF 1.687
Xingang Li,Chenggong Zheng,Zeli Wang,Hong Sui,Lin He
The key step for the adsorption-desorption engineering process is the reversible in-situ desorption of the adsorbent without VOCs (volatile organic compounds) accumulation. Our previous results show that the mesoporous silica gel performs well in adsorbing and desorbing the VOCs due to their capillary condensation in the mesopores. However, the microporous silica performs better in adsorbing though poorer in desorbing VOCs because of the direct interaction between VOCs molecules and the adsorbent wall in the micropores. Herein, the adsorption and desorption of o- xylene on two silica gels (SG) with different pore size distribution by vacuum swing adsorption (VSA) has been systematically studied. The equilibrium adsorption and desorption experiments of two kinds of silica gels at different loading heights in fixed bed show that the concentration front of o- xylene in microporous SG disperses slowly. However, the concentration front of o- xylene in mesoporous SG is significantly dispersed. To improve the overall efficiency of adsorption-desorption, the mesoporous and microporous SGs are loaded together in the fixed bed. It was found that the increase in the microporous SG loading percentage facilitated the adsorption capacity but deteriorated its desorption efficiency, while the opposite occurs to the mesoporous SG. After optimization, it was observed that minimal energy consumption (1.295 kWh/m 3 VOCs gas) was used when the adsorption column is loaded with 60% SG B at the inlet and 40% of the SG A at the outlet end for o- xylene vapour adsorption. This finding will be useful for designing adsorbent loading in the adsorption column.
研究领域:
化学工程
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环境科学
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DOI
高影响因子
Catalysts
·
2017
·Vol. 7
·期 8
·237
·
IF 3.082
Guo Qiu,Xincheng Wang,Chongpin Huang,Yingxia Li,Biaohua Chen
The production of bio-diesel fuels from carbohydrates is a promising alternative to fossil fuels with regard to the growing severity of the environmental problem and energy crisis. Potential bio-diesel candidates or additives, such as 5-(hydroxymethyl)-2-(dimethoxymethyl) furan (HDMF), 2-(dimethoxymethyl)-5-(methoxymethyl) furan (DMMF), and 5-(methoxymethyl)-2-furaldehyde (MMF) could be produced from the alcoholic solutions of both 5-HMF and fructose in the presence of solid acid catalysts. In the present study, a readily prepared, silica, gel-supported nitric acid (SiO2-HNO3) catalyst was found to be exceptionally reactive for the production of HDMF from fructose. A DMSO-methanol biphasic solvent system was developed and HDMF, DMMF, and MMF were observed at 150 °C, with maximum yields of 34%, 34%, and 25%, respectively. Meanwhile, a maximum HDMF yield of 77% was obtained from 5-HMF in methanol. Moreover, a sequential, one-pot, two-step dehydration/acetalization process, involving the dehydration of fructose to 5-HMF in dimethylsulfoxide (DMSO) at 150 °C, and followed by adding a certain amount of methanol to react with the formed 5-HMF to HDMF at 100 °C, was developed to promote the yield of HDMF. The optimum yield of HDMF reached 70% with the complete conversion of fructose. The reaction mechanisms of dehydration and acetalization have been proposed for the conversion of 5-HMF to HDMF. The two-step design allows for facile catalyst recycling while supplying as a promising method for the production of biodiesel from complex carbohydrates.Keywords:bio-diesel;silica gel-supported nitric acid;one-pot two-step system
研究领域:
化学工程
·
可再生能源
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产品关联
DOI
高影响因子
ANALYTICAL CHEMISTRY
·
2018
·
IF 6.042
Kun Qian,Zhanqiang Yang,Feifang Zhang,Bingcheng Yang,Purnendu K. Dasgupta
Bleeding of hydrophilic interaction liquid chromatographic (HILIC) phases is a major problem. A hydrophobic silica surface exhibits low bleeding but does not behave as a HILIC phase. A hydrophilic coating, such as that of poly(vinyl alcohol) (PVA) on a hydrophobic particle should result in a low-bleed hydrophilic phase. However, a silica particle functionalized in a hydrophobic manner is not wetted by PVA and cannot be coated with it. Coating with PVA becomes possible if one region of the hydrophobic functionality is polar. We describe a low-bleed HILIC stationary phase, PVA-coated benzylthioethyl-silica. The benzyl groups shield the silica from water erosion, while the thiol group provides sufficient local polarity for PVA to wet the material. The new stationary phase demonstrated good chromatographic performance and typical HILIC retention behavior. The measured silica concentration in the effluent was ∼80-fold lower than that from a bare silica column. The new stationary phase exhibited a lower background level, lower background noise, and lower background drift under gradient conditions than benchmark commercial columns.
研究领域:
分析化学
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色谱技术
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DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2025
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IF 9
Zilan Yin,Qidong Zhao,Chuyi Xie,Gaohong He,Yonghou Xiao
With the rapidly growing demand of high-purity methanol, developing high-efficiency adsorbents has become urgent to completely remove metal ions from methanol. Herein, a novel adsorbent, ethylenediaminetetraacetic acid (EDTA) modified silica gel (EDTA-2N-Silica) was successfully prepared for copper ions deep removal from methanol. EDTA-2N-Silica was constructed by using 3-(2-amino-ethylamino) propyl-trimethoxysilane (Silicone A-1120) to graft the EDTA molecules onto the silicon hydroxyl groups over silica gel. Dynamic adsorption experiments revealed that copper ions could be effectively removed from methanol prior to breakthrough point, with almost complete elimination achieved before adsorption column exhaustion. Correspondingly, the breakthrough and equilibrium adsorption capacities of copper ions over EDTA-2N-Silica-0.375 achieved 0.159 and 0.846 mmol g −1 at 40 °C, respectively. According to the density functional theory calculation, the enhanced copper ions capture performance of EDTA-2N-Silica was mainly attributed to the copper ions complexation with N-containing and the O-containing groups from EDTA. Furthermore, after the fifth regeneration, the equilibrium adsorption capacity of EDTA-2N-Silica-0.375 toward copper ions could retain 87.82 % that of the fresh sample, indicating its satisfactory regeneration performance. Considering its excellent adsorption and regeneration performance, EDTA-2N-Silica adsorbent is expected to be employed for efficient removal of trace copper ions from methanol.
研究领域:
化学工程
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环境科学
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产品关联
DOI
高影响因子
Frontiers of Chemical Science and Engineering
·
2020
·Vol. 14
·期 6
·1018-1028
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IF 3.552
Zeng Jiehui,Zeng Jianxian,Zhou Hu,Liu Guoqing,Yuan Zhengqiu,Jian Jian
An ion-imprinted sorbent (IIP) was prepared by using Ni 2+ as template, 3-[2-(2-aminoethylamino) ethylamino] propyl-trimethoxysilane as functional monomer, and silica gel as carrier. The adsorption performance of IIP towards Ni 2+ was investigated. IIP showed a higher adsorption capacity than that of non-imprinted sorbent, and it also exhibited high selectivity for Ni 2+ in the presence of Cu 2+ and Zn 2+ ions. Then, IIP was used to form a dynamic membrane onto the surface of ceramic membrane for treatment of electroplating wastewater containing Ni 2+ . Compared with ceramic membrane, IIP dynamic membrane had much higher steady membrane flux, and also rejected Ni 2+ to obtain a lower concentration of Ni 2+ in the permeate fluid. Perhaps it is suitable for future practice applications.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
Frontiers in Chemistry
·
2019
·
IF 3.782
Zhang Ying,Qu Rongjun,Xu Ting,Zhang Yu,Sun Changmei,Ji Chunnuan,Wang Ying
To further increase the quantity and density of functional groups on adsorbent, terminal triethylenetetramine hyperbranched dendrimer-like polymer modified silica-gel (SG-TETA and SG-TETA2) was synthesized. The hyperbranched dendrimer-like polymer was successfully introduced onto silica gel and new cavities were formed, which was demonstrated by FTIR, SEM, and BET. The highest adsorption capacities of SG-TETA and SG-TETA2 obtained from Langmuir model toward Au(III) were 2.11, and 2.27 mmol g−1, respectively, indicating that SG-TETA2 possessing more functional groups had a better adsorption ability. Moreover, the adsorbents combined with Au(III) ion through chelation and electrostatic attraction mechanism, after which reduction reactions for Au(III) ion loaded on adsorbents proceeded. SG-TETA2 had better adsorption selectivity than SG-TETA in removing Au(III) in Au-existed ion solution systems. SG-TETA2 had higher overall adsorption capacities compared to silica-gel-based hyperbranched polymers functionalized by diethylenetriamine. Therefore, the effective recovery makes SG-TETA2 a practical adsorbent in removing Au(III) ion from e-wastes and industrial effluents with much prospect.
研究领域:
材料科学
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环境科学
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产品关联
DOI
PubMed
高影响因子
NEW JOURNAL OF CHEMISTRY
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2022
·Vol. 46
·期 33
·15959-15966
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IF 3.925
Kai Zong,Ke Li,Ziyue Zhou,Lei Gong,Dongshun Deng
The uptake of NH3 in the industrial tail gas will improve the environmental quality for human health and ecology. Adsorption separation has the advantages of simple operation and low energy consumption. However, the relatively low adsorption capacity severely hinders its practical utilization. In this work, four glycerol-based deep eutectic solvents (DESs) were incorporated into porous silica gels (SGs) and Al2O3 with a large surface area and pore structure to form novel DES/SG and DES/Al2O3 composites. The obtained materials were systematically characterized by FTIR, SEM, BET, and TGA and further evaluated for NH3 adsorption. The results showed that the acidic GuSCN:Gly DES played an indispensable role for the high adsorption ability of the composite. 40 wt% GuSCN : Gly (1 : 3) DES/SG can capture 115.40 mg NH3 per gram adsorbent, which is better than most of the solid adsorption materials reported in the literature and even 30% higher than the original SG. The high adsorption capacity, outstanding thermal stability, and good reusability confirm the success of the present strategy. This study will provide a useful idea for designing DES-supported composites for NH3 separation applications.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
Journal of Food Measurement and Characterization
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2020
·Vol. 14
·期 4
·2134-2144
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IF 1.648
Huang Xin,Wang Li,Chen Jingyu,Jiang Chengyu,Wu Shijia,Wang Hongxin
Tea polyphenols (TPPs), as the most important functional component in tea extract, are easily contaminated by many heavy metals during tea processing, transportation and storage. TPPs with heavy metals can cause serious health problems and economic losses. In this study, to efficiently remove heavy metals from TPPs without affecting their active compounds and antioxidant functions, we prepared the amino-functionalized modified silica gel (AFSG) to remove Pb, Cu and Cd from TPPs, and determined removal rate of heavy metals, total polyphenolic content (TPC) and antioxidant activity of TPPs before and after adsorption. The static adsorption experiments showed that the adsorption isotherms were consistent with Langmuir model, in which the maximum sorption capacities of Pb, Cu and Cd were 140.23, 100.75 and 48.03 mg/g (25 °C, pH 5.0), respectively. Compared with before adsorption, the contents of Pb, Cu and Cd in 3 TPPs samples decreased significantly after adsorption on AFSG column (p < 0.01). However, the TPC and antioxidant capacity of the 3 TPPs samples had no significant effect before and after adsorption (p > 0.05). Meanwhile, the desorption and regeneration experiment showed that after 6 times of cyclic adsorption, the removal ability of Pb, Cu and Cd in TPPs by AFSG column could still reach 98.1%, 99.59% and 99.78%, respectively. Therefore, these results suggested that AFSG column could effectively remove heavy metals from TPPs without affecting the TPC and its antioxidant activity, it has potential applications in the removal and detection of heavy metals in TPPs.
研究领域:
食品科学
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环境科学
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产品关联
DOI
高影响因子
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
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2024
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IF 4.3
Yijie Wu,Mingzhu Li,Baoyang Liu,Yong Ren,Xuli Ding
Silicon oxides are considered as potential anode materials for next generation lithium-ion batteries owing to their high specific capacity, low cost and suitable work voltage. However, the commercial advance has been impeded by their intrinsic low conductivity and severe volume change. In order to overcome the above issues, herein, a porous SiO 2 combing with Zn nanoparticle (SG@Zn) composite is designed and prepared by a simple but effective melt-self-assembly method, in which, SiO 2 is obtained from the silica gel. The presence of Zn not only improves the cyclic stability but also enhances the diffusion kinetics of Li + ion in the SiO 2 anodes. As expected, the fabricated SG@Zn anode has a high initial capacity of 830 mA h g −1 and the capacity maintaining ratio reaches 72 % after 300 cycles. It is worth noting that the rate performance is also boosted significantly, delivering capacity up to 455 mA h g − 1 at current density of 800 mA g − 1 , which is superior to the single silica gel anode. The electrochemical performance measurement results indicate the great potential of the prepared SG@Zn composite as a high-performance and low-cost anode material for the next generation high-specific-energy lithium-ion batteries.
研究领域:
材料科学
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电化学
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产品关联
DOI
高影响因子
Polymers
·
2022
·Vol. 14
·期 14
·2894
·
IF 4.967
Jia Qu,Qiang Yang,Wei Gong,Meilan Li,Baoyue Cao
Heavy metal ions and organic pollutants often coexist in industrial effluents. In this work, silica-di-block polymer hybrids (SiO2-g-PBA-b-PDMAEMA) with two ratios (SiO2/BA/DMAEMA = 1/50/250 and 1/60/240) were designed and prepared for the simultaneous removal of Cr(VI) and phenol via a surface-initiated atom-transfer radical polymerization process using butyl methacrylate (BA) as a hydrophobic monomer and 2-(Dimethylamino)ethylmethacrylate (DMAEMA) as a hydrophilic monomer. The removal efficiency of Cr(VI) and phenol by the hybrids reached 88.25% and 88.17%, respectively. The sample with a larger proportion of hydrophilic PDMAEMA showed better adsorption of Cr(VI), and the sample with a larger proportion of hydrophobic PBA showed better adsorption of phenol. In binary systems, the presence of Cr(VI) inhibited the adsorption of phenol, yet the presence of phenol had a negligible effect on the adsorption of Cr(VI). Kinetics studies showed that the adsorption of Cr(VI) and phenol fitted the pseudo-second-order model well. Thermodynamic studies showed that the adsorption behavior of Cr(VI) and phenol were better described by the Langmuir adsorption isotherm equation, and the adsorption of Cr(VI) and phenol were all spontaneous adsorptions driven by enthalpy. The adsorbent still possessed good adsorption capacity for Cr(VI) and phenol after six adsorption–desorption cycles. These findings show that SiO2-g-PBA-b-PDMAEMA hybrids represent a satisfying adsorption material for the simultaneous removal of heavy metal ions and organic pollutants.Keywords:silica;amphipathic;block copolymer;adsorption;Cr(VI);phenol
研究领域:
环境科学
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材料科学
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DOI
PubMed
高影响因子
CHEMOSPHERE
·
2022
·
IF 8.943
Zhengnan Tu,Yumeng Qi,Ruijuan Qu,Xiaosheng Tang,Zunyao Wang,Zongli Huo
As one of the first batch of persistent organic pollutants (POPs) included in Stockholm Convention , hexachlorobenzene (HCB) has attracted great attention because of its wide occurrence and great environmental risks. Considering the easy adsorption of HCB on solids and the complexity of natural particles, we systematically investigated the photodegradation of HCB on the surface of silica gel (SG) in aqueous solution in this work to reveal its fate in natural waters. Under mercury lamp irradiation, more than 90% of HCB loaded on SG could be removed after 240 min. Moreover, the effects of solution pH and water constituents were examined, and results showed that the presence of NO 2 − , NO 3 − , Fe 3+ and humic acid (HA) significantly inhibited the reaction due to the scavenging of ROS and/or competitive absorption of light. According to radical quenching experiments and electron paramagnetic resonance (EPR) spectra, hydroxyl radicals and singlet oxygen generated on the surface of SG could participate in the transformation of HCB, but •OH played a dominant role. Based on products identified by high performance liquid chromatography-mass spectrometry (HPLC-MS) and gas chromatography-mass spectrometry (GC-MS), two main pathways were proposed for the removal of HCB, including dechlorination and hydroxylation which represent direct and indirect photodegradation, respectively, and the occurrence of these two reactions was further supported by density functional theory (DFT) calculations. From the quantitative analysis of penta-chlorobenzene, it was estimated that dechlorination and hydroxylation contributed to approximately 44.4% and 55.6% of initial HCB degradation, respectively. Furthermore, toxicity predictions by the ecological structure–activity relationship model (ECOSAR) suggested that the toxicity of HCB was decreased in the photodegradation process. This study would provide important information for understanding the photochemical transformation mechanism of HCB at the solid/water interface.
研究领域:
环境科学
·
化学
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DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2023
·
IF 5.2
Na Li,Yong Li,Ruitao Lou,Rongwei Xiong,Hong Xu
The release of internal pollutants in shallow lakes is a widely concerning environmental issue. Colloids widely existing in eutrophic shallow lakes will affect the release and migration of pollutants. In this context, the different effects of two colloids [humic acid (HA) and silica (SiO 2 )], either individual or in coexistence, on the adsorption and migration of ammonia nitrogen (NH 4 + -N) in sediments under different ionic strengths (IS) were analyzed, through a series of batch and column experiments. It was found that, under a relatively low IS condition (1 mM Na + ), SiO 2 colloids greatly enhanced the mobility of NH 4 + -N in sediments. With IS increased (20 mM Na + ), the presence of colloids exhibited an impeding effect on the mobility of NH 4 + -N due to colloidal flocculation and precipitation. While HA colloids largely suppressed the mobility of NH 4 + -N in sediments under either low or high IS conditions. HA colloids are more likely to form aggregates and have more adsorption sites than SiO 2 colloids. In the NH 4 + -N–SiO 2 –HA system, HA colloids also showed a retardant effect on the transport of both SiO 2 colloids and NH 4 + -N, and the retardant effect increased with the increase of HA colloid concentration. Exchange coordination and hydrogen bond force, as well as the decreased stability of the colloid system, played an important role in such a retardant effect, which consequently resulted in more NH 4 + -N adsorption. The transport of colloids in the NH 4 + -N–colloids co-transport system can be successfully described by Derjaguin–Landau–Verwey–Overbeek (DLVO) theory. In addition, with an increase of IS, NH 4 + -N transport was enhanced because of competitive adsorption of the cations and NH 4 + -N on colloids and the porous medium . These results implied that abundant HA colloids and low ion concentration can reduce the risk of NH 4 + -N release and migration in sediments and consequently its exchange flux across the sediment-water interface.
研究领域:
环境科学
·
水文学
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DOI
高影响因子
危险品化学品经营许可证（带存储）