The utilization of chemical reactions is crucial in various industrial processes, including pharmaceutical synthesis and the production of fine chemicals. However, traditional chemical catalysts often lack selectivity, require harsh reaction conditions, and lead to the generation of hazardous waste. In response, biocatalysis has emerged as a promising approach within green chemistry, employing enzymes as catalysts. Among these enzymes, aldolases have gained attention for their efficiency and selectivity in catalyzing C-C bond formation, making them versatile biocatalysts for diverse biotechnological applications. Despite their potential, challenges exist in aldolase-based biocatalysis, such as limited availability of natural aldolases with desired catalytic properties. This review explores strategies to address these challenges, including immobilization techniques, recombinant expression, and protein engineering approaches. By providing valuable insights into the suitability of aldolases as biocatalysts, this review lays the groundwork for future research and the exploration of innovative strategies to fully harness the potential of aldolases in biotechnology. This comprehensive review aims to attract readers by providing a comprehensive overview of aldolase-based biocatalysis, addressing challenges, and proposing avenues for future research and development.
{"title":"Aldolase: A Desirable Biocatalytic Candidate for Biotechnological Applications","authors":"Moloko G. Mathipa-Mdakane, Lucia Steenkamp","doi":"10.3390/catal14020114","DOIUrl":"https://doi.org/10.3390/catal14020114","url":null,"abstract":"The utilization of chemical reactions is crucial in various industrial processes, including pharmaceutical synthesis and the production of fine chemicals. However, traditional chemical catalysts often lack selectivity, require harsh reaction conditions, and lead to the generation of hazardous waste. In response, biocatalysis has emerged as a promising approach within green chemistry, employing enzymes as catalysts. Among these enzymes, aldolases have gained attention for their efficiency and selectivity in catalyzing C-C bond formation, making them versatile biocatalysts for diverse biotechnological applications. Despite their potential, challenges exist in aldolase-based biocatalysis, such as limited availability of natural aldolases with desired catalytic properties. This review explores strategies to address these challenges, including immobilization techniques, recombinant expression, and protein engineering approaches. By providing valuable insights into the suitability of aldolases as biocatalysts, this review lays the groundwork for future research and the exploration of innovative strategies to fully harness the potential of aldolases in biotechnology. This comprehensive review aims to attract readers by providing a comprehensive overview of aldolase-based biocatalysis, addressing challenges, and proposing avenues for future research and development.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140471995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Antonopoulou, Anna Tzamaria, Kleopatra Miserli, Christos Lykos, Ioannis Konstantinou
In the present study, the photocatalytic oxidation and detoxification of aqueous matrices contaminated with boscalid using g-C3N4 catalyst and UV-A light was investigated. The UV-A/g-C3N4 process was found to achieve higher than 83% removal of boscalid in both matrices, with h+ and O2•− being the main species. UHPLC-HRMS analysis allowed the identification of five TPs, while the main degradation pathways involved hydroxylation, cyclization, and dechlorination. Scenedesmus rubescens microalgae species was exposed to boscalid solutions and lake water spiked with the fungicide before the photocatalytic treatment and inhibition in the growth rate was observed. An increase in the toxicity was also observed during the first stages of the treatment. The results from the in silico study correlate with the observed evolution of ecotoxicity during the application of the process, as some of the identified TPs were found to be toxic or very toxic for aquatic organisms. However, prolonged application of the process can lead to detoxification. It was also observed that the g-C3N4 catalyst can retain its photochemical stability and activity after at least three cycles. However, a slight decrease in the activity was observed when repeated another two times. This study demonstrated that the suggested photocatalytic process can both decrease the harmful effects of boscalid as well as effectively lower its concentration in water.
{"title":"Heterogeneous Photocatalytic Oxidation and Detoxification of Simulated Agricultural Wastewater Contaminated with Boscalid Fungicide Using g-C3N4 Catalyst","authors":"M. Antonopoulou, Anna Tzamaria, Kleopatra Miserli, Christos Lykos, Ioannis Konstantinou","doi":"10.3390/catal14020112","DOIUrl":"https://doi.org/10.3390/catal14020112","url":null,"abstract":"In the present study, the photocatalytic oxidation and detoxification of aqueous matrices contaminated with boscalid using g-C3N4 catalyst and UV-A light was investigated. The UV-A/g-C3N4 process was found to achieve higher than 83% removal of boscalid in both matrices, with h+ and O2•− being the main species. UHPLC-HRMS analysis allowed the identification of five TPs, while the main degradation pathways involved hydroxylation, cyclization, and dechlorination. Scenedesmus rubescens microalgae species was exposed to boscalid solutions and lake water spiked with the fungicide before the photocatalytic treatment and inhibition in the growth rate was observed. An increase in the toxicity was also observed during the first stages of the treatment. The results from the in silico study correlate with the observed evolution of ecotoxicity during the application of the process, as some of the identified TPs were found to be toxic or very toxic for aquatic organisms. However, prolonged application of the process can lead to detoxification. It was also observed that the g-C3N4 catalyst can retain its photochemical stability and activity after at least three cycles. However, a slight decrease in the activity was observed when repeated another two times. This study demonstrated that the suggested photocatalytic process can both decrease the harmful effects of boscalid as well as effectively lower its concentration in water.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140472741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dalsan Yoo, Munjeong Kim, Seung Kyo Oh, Seoyeon Hwang, Sohee Kim, Wooram Kim, Yoonja Kwon, Youngmin Jo, Jong-Ki Jeon
The objectives of this study were to prepare a high-purity hydroxylammonium nitrate (HAN) solution and evaluate the performance of various types of metal oxide/honeycomb catalysts during the catalytic decomposition of the HAN solution. Hydroxylammonium nitrate was prepared via a neutralization reaction of hydroxylamine and nitric acid. FT-IR was used to analyze the chemical composition, chemical structure, and functional groups of the HAN. The aqueous HAN solution obtained from pH 7.06 showed the highest concentration of HAN of 60% and a density of 1.39 g/mL. The concentration of HAN solution that could be obtained when the solvent was evaporated to the maximum level could not exceed 80%. In this study, catalysts were prepared using a honeycomb structure made of cordierite (5SiO2-2MgO-2Al2O3) as a support, with Mn, Co, Cu, Pt, or Ir impregnated as active metals. The pore structure of the metal oxide/honeycomb catalysts did not significantly depend on the type of metal loaded. The Cu/honeycomb catalyst showed the strongest effect of lowering the decomposition onset temperature in the decomposition of the HAN solution likely due to the intrinsic activity of the Cu metal being superior to that of the other metals. It was confirmed that the effect of the catalyst on the decomposition mechanism of the aqueous HAN solution was negligible. Through a repetitive cycle of HAN decomposition, it was confirmed that the Cu/honeycomb catalyst could be recovered and reused as a catalyst for the decomposition of an aqueous HAN solution.
本研究的目的是制备高纯度羟基硝酸铵（HAN）溶液，并评估各种类型的金属氧化物/蜂窝催化剂在催化分解 HAN 溶液过程中的性能。羟基硝酸铵是通过羟胺和硝酸的中和反应制备的。傅立叶变换红外光谱用于分析 HAN 的化学成分、化学结构和官能团。pH 值为 7.06 的 HAN 水溶液显示 HAN 的最高浓度为 60%，密度为 1.39 g/mL。当溶剂蒸发到最大程度时，HAN 溶液的浓度不会超过 80%。本研究以堇青石（5SiO2-2MgO-2Al2O3）制成的蜂窝结构为载体，浸渍 Mn、Co、Cu、Pt 或 Ir 等活性金属，制备了催化剂。金属氧化物/蜂窝状催化剂的孔隙结构与负载的金属类型无明显关系。在 HAN 溶液的分解过程中，铜/蜂窝催化剂降低分解起始温度的效果最强，这可能是由于铜金属的内在活性优于其他金属。经证实，催化剂对 HAN 水溶液分解机理的影响微乎其微。通过 HAN 分解的重复循环，证实铜/蜂窝催化剂可以回收并作为催化剂重新用于 HAN 水溶液的分解。
{"title":"Synthesis of Hydroxylammonium Nitrate and Its Decomposition over Metal Oxide/Honeycomb Catalysts","authors":"Dalsan Yoo, Munjeong Kim, Seung Kyo Oh, Seoyeon Hwang, Sohee Kim, Wooram Kim, Yoonja Kwon, Youngmin Jo, Jong-Ki Jeon","doi":"10.3390/catal14020116","DOIUrl":"https://doi.org/10.3390/catal14020116","url":null,"abstract":"The objectives of this study were to prepare a high-purity hydroxylammonium nitrate (HAN) solution and evaluate the performance of various types of metal oxide/honeycomb catalysts during the catalytic decomposition of the HAN solution. Hydroxylammonium nitrate was prepared via a neutralization reaction of hydroxylamine and nitric acid. FT-IR was used to analyze the chemical composition, chemical structure, and functional groups of the HAN. The aqueous HAN solution obtained from pH 7.06 showed the highest concentration of HAN of 60% and a density of 1.39 g/mL. The concentration of HAN solution that could be obtained when the solvent was evaporated to the maximum level could not exceed 80%. In this study, catalysts were prepared using a honeycomb structure made of cordierite (5SiO2-2MgO-2Al2O3) as a support, with Mn, Co, Cu, Pt, or Ir impregnated as active metals. The pore structure of the metal oxide/honeycomb catalysts did not significantly depend on the type of metal loaded. The Cu/honeycomb catalyst showed the strongest effect of lowering the decomposition onset temperature in the decomposition of the HAN solution likely due to the intrinsic activity of the Cu metal being superior to that of the other metals. It was confirmed that the effect of the catalyst on the decomposition mechanism of the aqueous HAN solution was negligible. Through a repetitive cycle of HAN decomposition, it was confirmed that the Cu/honeycomb catalyst could be recovered and reused as a catalyst for the decomposition of an aqueous HAN solution.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140472610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The use of eco-friendly biomass as a resource is an efficient way to address the problems of fossil fuel depletion and climate change. In biomass conversion, versatile γ-valerolactone (GVL) is generally obtained from levulinic acid (LA) hydrogenation via a multimetallic catalyst system. Despite conversion efficiency being enhanced in mild conditions due to metal interactions, maintaining high catalyst stability is still a challenge. In this study, we synthesized a surrounded Co0.52Ni0.48@Al2O3-IE catalyst that exhibited excellent alloying and synergistic interaction between the metal constituents. Under relatively mild reaction conditions, the GVL yield over the catalyst exceeded 99% in LA hydrogenation. The catalyst showed no deactivation in a test of five cycles, displaying superiority in stability, possibly due to reasons of the physical isolation of the shell and the alumina retention on the Co-Ni alloys surface caused by the reversibility of exchange equilibrium. The present work demonstrated that a surrounded structured catalyst fabricated by ion exchange (IE) with active metals physically enclosed can lead to high catalytic activity and superior stability.
利用生态友好型生物质作为资源是解决化石燃料枯竭和气候变化问题的有效途径。在生物质转化过程中，多功能γ-戊内酯（GVL）通常是通过多金属催化剂系统从左旋乙酸（LA）氢化反应中获得的。尽管由于金属间的相互作用，转化效率在温和条件下得到了提高，但保持催化剂的高稳定性仍然是一项挑战。在本研究中，我们合成了一种环绕型 Co0.52Ni0.48@Al2O3-IE 催化剂，该催化剂表现出金属成分之间良好的合金化和协同作用。在相对温和的反应条件下，该催化剂在 LA 加氢反应中的 GVL 收率超过 99%。该催化剂在五次循环测试中未出现失活现象，显示出卓越的稳定性，这可能是由于外壳的物理隔离以及交换平衡的可逆性导致氧化铝保留在 Co-Ni 合金表面。本研究结果表明，通过离子交换（IE）技术制造的活性金属物理封闭的环绕结构催化剂可以获得高催化活性和卓越的稳定性。
{"title":"Ion-Exchange Synthesis of Surrounded CoNi@Al2O3 Catalyst for Levulinic Acid Hydrogenation to γ-Valerolactone under Mild Conditions","authors":"Hongzhi Ding, Chenyu Yang, Congyan Jiang, Wei Luo, Qiuyue Wang, Xuefeng Guo","doi":"10.3390/catal14020113","DOIUrl":"https://doi.org/10.3390/catal14020113","url":null,"abstract":"The use of eco-friendly biomass as a resource is an efficient way to address the problems of fossil fuel depletion and climate change. In biomass conversion, versatile γ-valerolactone (GVL) is generally obtained from levulinic acid (LA) hydrogenation via a multimetallic catalyst system. Despite conversion efficiency being enhanced in mild conditions due to metal interactions, maintaining high catalyst stability is still a challenge. In this study, we synthesized a surrounded Co0.52Ni0.48@Al2O3-IE catalyst that exhibited excellent alloying and synergistic interaction between the metal constituents. Under relatively mild reaction conditions, the GVL yield over the catalyst exceeded 99% in LA hydrogenation. The catalyst showed no deactivation in a test of five cycles, displaying superiority in stability, possibly due to reasons of the physical isolation of the shell and the alumina retention on the Co-Ni alloys surface caused by the reversibility of exchange equilibrium. The present work demonstrated that a surrounded structured catalyst fabricated by ion exchange (IE) with active metals physically enclosed can lead to high catalytic activity and superior stability.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140476996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Oumaima Cherni, Diego Carballares, El-Hocine Siar, Pedro Abellanas-Perez, Diandra de Andrades, J. Rocha-Martín, Sellema Bahri, Roberto Fernandez-Lafuente
The lipase from Prunus dulcis almonds has been immobilized for the first time. For this purpose, two different supports, an octadecyl methacrylate particulate support, and aminated agarose (monoaminoethyl-N-aminoethyl) have been utilized. Both immobilized biocatalysts show improved enzyme stability, but great changes in enzyme specificity were detected. The enzyme immobilized via ion exchange maintained its activity intact versus p-nitrophenyl butyrate, while the enzyme immobilized on the hydrophobic support fully lost its activity versus this substrate, which was confirmed to be due to substrate adsorption on the support. However, this biocatalyst was much more active versus triacetin (more than 10-fold), R- or S- methyl mandelate at pH 7. At pH 9, a strong effect of using phosphate or bicarbonate as reaction buffers was detected. Using bicarbonate, the interfacially immobilized enzyme presented no activity versus R-isomer, but it was very active versus the S-isomer and triacetin. Using a phosphate buffer during the reaction, all compounds were recognized as substrates. The enzyme immobilized via ion exchange was significantly more active using phosphate; in fact, using bicarbonate, the enzyme was inactive versus both methyl mandelate isomers. This paper shows for the first time a great interaction between the effects of the immobilization protocol and buffer used during reaction on the enantiospecificity of lipases.
{"title":"Tuning Almond Lipase Features by Using Different Immobilization Supports","authors":"Oumaima Cherni, Diego Carballares, El-Hocine Siar, Pedro Abellanas-Perez, Diandra de Andrades, J. Rocha-Martín, Sellema Bahri, Roberto Fernandez-Lafuente","doi":"10.3390/catal14020115","DOIUrl":"https://doi.org/10.3390/catal14020115","url":null,"abstract":"The lipase from Prunus dulcis almonds has been immobilized for the first time. For this purpose, two different supports, an octadecyl methacrylate particulate support, and aminated agarose (monoaminoethyl-N-aminoethyl) have been utilized. Both immobilized biocatalysts show improved enzyme stability, but great changes in enzyme specificity were detected. The enzyme immobilized via ion exchange maintained its activity intact versus p-nitrophenyl butyrate, while the enzyme immobilized on the hydrophobic support fully lost its activity versus this substrate, which was confirmed to be due to substrate adsorption on the support. However, this biocatalyst was much more active versus triacetin (more than 10-fold), R- or S- methyl mandelate at pH 7. At pH 9, a strong effect of using phosphate or bicarbonate as reaction buffers was detected. Using bicarbonate, the interfacially immobilized enzyme presented no activity versus R-isomer, but it was very active versus the S-isomer and triacetin. Using a phosphate buffer during the reaction, all compounds were recognized as substrates. The enzyme immobilized via ion exchange was significantly more active using phosphate; in fact, using bicarbonate, the enzyme was inactive versus both methyl mandelate isomers. This paper shows for the first time a great interaction between the effects of the immobilization protocol and buffer used during reaction on the enantiospecificity of lipases.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140472339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The catalytic oxidation of hydrocarbons stands at the forefront of sustainable chemical transformations, offering pathways to selectively convert aliphatic and aromatic compounds into valuable oxygenated products [...]
{"title":"Catalytic Oxidation of Hydrocarbons","authors":"S. Carabineiro","doi":"10.3390/catal14020111","DOIUrl":"https://doi.org/10.3390/catal14020111","url":null,"abstract":"The catalytic oxidation of hydrocarbons stands at the forefront of sustainable chemical transformations, offering pathways to selectively convert aliphatic and aromatic compounds into valuable oxygenated products [...]","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140476780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Three-dimensional printed electrodes seem to overcome many structural and operational limitations compared to ones fabricated with conventional methods. Compared to other 3D printing techniques, direct ink writing (DIW), as a sub-category of extrusion-based 3D printing techniques, allows for easier fabrication, the utilization of various materials, and high flexibility in electrode architectures with low costs. Despite the conveniences in fabrication procedures that are facilitated by DIW, what qualifies an ink as 3D printable has become challenging to discern. Probing rheological ink properties such as viscoelastic moduli and yield stress appears to be a promising approach to determine 3D printability. Yet, issues arise regarding standardization protocols. It is essential for the ink filament to be extruded easily and continuously to maintain dimensional accuracy, even after post-processing methods related to electrode fabrication. Additives frequently present in the inks need to be removed, and this procedure affects the electrical and electrochemical properties of the 3D-printed electrodes. In this context, the aim of the current review was to analyze various energy devices, highlighting the type of inks synthesized and their measured rheological properties. This review fills a gap in the existing literature. Thus, according to the inks that have been formulated, we identified two categories of DIW electrode architectures that have been manufactured: supported and free-standing architectures.
与传统方法相比，三维打印电极似乎克服了许多结构和操作限制。与其他三维打印技术相比，作为基于挤压的三维打印技术的一个子类别，直接墨水写入（DIW）可以更容易地制造、使用各种材料，并以较低的成本实现电极结构的高度灵活性。尽管 DIW 为制造程序提供了便利，但如何判定一种油墨是否可用于 3D 打印却成为一项挑战。探测墨水的流变特性（如粘弹性模量和屈服应力）似乎是确定 3D 可打印性的一种可行方法。然而，在标准化协议方面也出现了问题。即使在采用与电极制造相关的后处理方法后，油墨丝也必须能够轻松、连续地挤出，以保持尺寸精度。油墨中经常出现的添加剂需要去除，而这一过程会影响 3D 打印电极的电气和电化学特性。在此背景下，本综述旨在分析各种能源设备，重点介绍合成油墨的类型及其测得的流变特性。本综述填补了现有文献的空白。因此，根据已配制的油墨，我们确定了已制造的 DIW 电极结构的两个类别：支撑结构和独立结构。
{"title":"Direct Ink Writing for Electrochemical Device Fabrication: A Review of 3D-Printed Electrodes and Ink Rheology","authors":"N. Polychronopoulos, Angeliki Brouzgou","doi":"10.3390/catal14020110","DOIUrl":"https://doi.org/10.3390/catal14020110","url":null,"abstract":"Three-dimensional printed electrodes seem to overcome many structural and operational limitations compared to ones fabricated with conventional methods. Compared to other 3D printing techniques, direct ink writing (DIW), as a sub-category of extrusion-based 3D printing techniques, allows for easier fabrication, the utilization of various materials, and high flexibility in electrode architectures with low costs. Despite the conveniences in fabrication procedures that are facilitated by DIW, what qualifies an ink as 3D printable has become challenging to discern. Probing rheological ink properties such as viscoelastic moduli and yield stress appears to be a promising approach to determine 3D printability. Yet, issues arise regarding standardization protocols. It is essential for the ink filament to be extruded easily and continuously to maintain dimensional accuracy, even after post-processing methods related to electrode fabrication. Additives frequently present in the inks need to be removed, and this procedure affects the electrical and electrochemical properties of the 3D-printed electrodes. In this context, the aim of the current review was to analyze various energy devices, highlighting the type of inks synthesized and their measured rheological properties. This review fills a gap in the existing literature. Thus, according to the inks that have been formulated, we identified two categories of DIW electrode architectures that have been manufactured: supported and free-standing architectures.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140484630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Juan C. Aldana, Marta Pedrosa, Adrián M. T. Silva, Joaquim L. Faria, Juan L. Acero, Pedro M. Álvarez
In this study, a mixed-matrix method was used to prepare PVDF polymeric membranes with different amounts of TiO2 P25 photocatalyst embedded, which were employed in filtration processes in the presence of UV radiation (LED, peak emission at 375 nm) to eliminate two aqueous micropollutants (MPs) used as model compounds (venlafaxine and metoprolol). The obtained membranes were characterized to gain insights into their texture, morphology, composition, and other catalyst-related properties that could affect the photocatalytic filtration process. For that purpose, N2 adsorption–desorption, contact angle, SEM-EDX, thermal analysis, FTIR, XPS, UV-vis DRS, and PL spectroscopy were used. Filtration tests were carried out in continuous mode using a dead-end filtration cell to evaluate the performance of the prepared membranes in removing the selected MPs. Experiments were performed both in ultrapure water and a secondary effluent from a municipal wastewater treatment plant. It was found that the synthesized membranes could effectively remove the target MPs in ultrapure water, achieving up to 99% elimination. Such process performance decreased drastically in the secondary effluent with removals below 35%. Carbonate/bicarbonate ions in the secondary effluent were identified as the main scavenging substances. Thus, after the partial removal of carbonate/bicarbonate ions from the secondary effluent, the removal of MPs achieved was above 60%.
{"title":"Nanocomposite PVDF/TiO2 Photocatalytic Membranes for Micropollutant Removal in Secondary Effluent","authors":"Juan C. Aldana, Marta Pedrosa, Adrián M. T. Silva, Joaquim L. Faria, Juan L. Acero, Pedro M. Álvarez","doi":"10.3390/catal14020109","DOIUrl":"https://doi.org/10.3390/catal14020109","url":null,"abstract":"In this study, a mixed-matrix method was used to prepare PVDF polymeric membranes with different amounts of TiO2 P25 photocatalyst embedded, which were employed in filtration processes in the presence of UV radiation (LED, peak emission at 375 nm) to eliminate two aqueous micropollutants (MPs) used as model compounds (venlafaxine and metoprolol). The obtained membranes were characterized to gain insights into their texture, morphology, composition, and other catalyst-related properties that could affect the photocatalytic filtration process. For that purpose, N2 adsorption–desorption, contact angle, SEM-EDX, thermal analysis, FTIR, XPS, UV-vis DRS, and PL spectroscopy were used. Filtration tests were carried out in continuous mode using a dead-end filtration cell to evaluate the performance of the prepared membranes in removing the selected MPs. Experiments were performed both in ultrapure water and a secondary effluent from a municipal wastewater treatment plant. It was found that the synthesized membranes could effectively remove the target MPs in ultrapure water, achieving up to 99% elimination. Such process performance decreased drastically in the secondary effluent with removals below 35%. Carbonate/bicarbonate ions in the secondary effluent were identified as the main scavenging substances. Thus, after the partial removal of carbonate/bicarbonate ions from the secondary effluent, the removal of MPs achieved was above 60%.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140491276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sergey A. Smirnov, R. M. Mensharapov, D. D. Spasov, Nataliya A. Ivanova, Sergey A. Grigoriev
Platinum electrocatalysts on graphene-like supports have recently attracted research interest as components of electrochemical devices based on hydrogen oxidation reactions in acid media due to their improved electrochemical properties, high stability, and conductivity. Within the current work, hydrogen adsorption and the recombination effects of a proton and hydroxonium on a graphene-based electrocatalyst were investigated using density functional theory. The interaction between ions and the platinum surface was simulated for various configurations, including different initial ion distances and angles relative to the surface of the graphene sheet as well as different adsorptions on various Pt atoms (vertices or faces for Pt13 and Pt14 nanoclusters). Then, the geometry optimization was performed. Changes in the density of states during the reactions were studied to analyze the occurrences and alterations of the interactions. A comparative analysis of the obtained adsorption energies of H+ and H3O+ with experimental data was conducted. The energy was calculated to be less in absolute value, and intermediates were more stable in adsorption models with the H–Pt–Gr angle of 90° than in models with the angle of 180°. Strong chemical bonding for models with H–Pt distances less than 2 Å was observed from the DOS.
石墨烯类载体上的铂电催化剂因其改善的电化学特性、高稳定性和导电性，最近引起了研究人员的兴趣，被用作基于酸性介质中氢气氧化反应的电化学装置的组件。在目前的研究工作中，使用密度泛函理论研究了质子和氢氧根在石墨烯基电催化剂上的氢吸附和重组效应。模拟了不同配置下离子与铂表面的相互作用，包括离子相对于石墨烯片表面的不同初始距离和角度，以及不同铂原子（Pt13 和 Pt14 纳米簇的顶点或面）上的不同吸附。然后，进行几何优化。研究了反应过程中状态密度的变化，以分析相互作用的发生和改变。对获得的 H+ 和 H3O+ 吸附能与实验数据进行了对比分析。计算得出的能量绝对值较小，H-Pt-Gr 夹角为 90°的吸附模型的中间产物比夹角为 180°的模型更稳定。从 DOS 观察到，H-Pt 间距小于 2 Å 的模型具有很强的化学键。
{"title":"Adsorption and Recombination of H+ and H3O+ on Graphene-Supported Pt1, Pt13, and Pt14 Nanoclusters: A First Principles Study","authors":"Sergey A. Smirnov, R. M. Mensharapov, D. D. Spasov, Nataliya A. Ivanova, Sergey A. Grigoriev","doi":"10.3390/catal14020108","DOIUrl":"https://doi.org/10.3390/catal14020108","url":null,"abstract":"Platinum electrocatalysts on graphene-like supports have recently attracted research interest as components of electrochemical devices based on hydrogen oxidation reactions in acid media due to their improved electrochemical properties, high stability, and conductivity. Within the current work, hydrogen adsorption and the recombination effects of a proton and hydroxonium on a graphene-based electrocatalyst were investigated using density functional theory. The interaction between ions and the platinum surface was simulated for various configurations, including different initial ion distances and angles relative to the surface of the graphene sheet as well as different adsorptions on various Pt atoms (vertices or faces for Pt13 and Pt14 nanoclusters). Then, the geometry optimization was performed. Changes in the density of states during the reactions were studied to analyze the occurrences and alterations of the interactions. A comparative analysis of the obtained adsorption energies of H+ and H3O+ with experimental data was conducted. The energy was calculated to be less in absolute value, and intermediates were more stable in adsorption models with the H–Pt–Gr angle of 90° than in models with the angle of 180°. Strong chemical bonding for models with H–Pt distances less than 2 Å was observed from the DOS.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140492646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recently, supported WO3-based catalysts have been widely used in oxidative desulfurization (ODS) due to their advantages of easy separation, high activity, and being environment-friendly. In this work, supported mesoporous WO3/SiO2 catalysts have been prepared using an incipient-wetness impregnation method with agricultural waste rice husks as both a silicon source and mesoporous template, and phosphotungstic acid as a tungsten source. The effects of different calcination temperatures and WO3 loadings on the ODS performance of samples are studied, and the appropriate calcination temperature and WO3 loading are 923 K and 15.0 wt.%, respectively. The relevant characterization results show that, compared with pure WO3, the specific surface area and mesopore volume of WO3/SiO2 samples are greatly increased. Due to (a) high WO3 loading, (b) high specific surface area, and (c) nanoscale WO3 grains uniformly dispersed on the surface of the mesoporous SiO2 carrier, active sites of WO3/SiO2 catalysts are greatly increased, and their catalytic activities are improved. After the sixth and eighth runs in the ODS of dibenzothiophene and 4,6-dimethyldibenzothiophene, respectively, the WO3/SiO2 catalyst still maintains high catalytic activity (>99.0%) despite the presence of a partial loss of WO3. In addition, with the aid of the UV-Vis technique, the tungsten-peroxo species, the active intermediates in the ODS reaction catalyzed by the WO3/SiO2 catalyst, are captured. Finally, a possible mechanism for the ODS of bulky organic sulfides using the WO3/SiO2 catalyst is proposed.
{"title":"The Green Preparation of Mesoporous WO3/SiO2 and Its Application in Oxidative Desulfurization","authors":"Yinhai Zhang, Xiaoxue Liu, Ruyu Zhao, Jingwei Zhang, Lanfen Zhang, Wei Zhang, Jian Hu, Hao Li","doi":"10.3390/catal14020103","DOIUrl":"https://doi.org/10.3390/catal14020103","url":null,"abstract":"Recently, supported WO3-based catalysts have been widely used in oxidative desulfurization (ODS) due to their advantages of easy separation, high activity, and being environment-friendly. In this work, supported mesoporous WO3/SiO2 catalysts have been prepared using an incipient-wetness impregnation method with agricultural waste rice husks as both a silicon source and mesoporous template, and phosphotungstic acid as a tungsten source. The effects of different calcination temperatures and WO3 loadings on the ODS performance of samples are studied, and the appropriate calcination temperature and WO3 loading are 923 K and 15.0 wt.%, respectively. The relevant characterization results show that, compared with pure WO3, the specific surface area and mesopore volume of WO3/SiO2 samples are greatly increased. Due to (a) high WO3 loading, (b) high specific surface area, and (c) nanoscale WO3 grains uniformly dispersed on the surface of the mesoporous SiO2 carrier, active sites of WO3/SiO2 catalysts are greatly increased, and their catalytic activities are improved. After the sixth and eighth runs in the ODS of dibenzothiophene and 4,6-dimethyldibenzothiophene, respectively, the WO3/SiO2 catalyst still maintains high catalytic activity (>99.0%) despite the presence of a partial loss of WO3. In addition, with the aid of the UV-Vis technique, the tungsten-peroxo species, the active intermediates in the ODS reaction catalyzed by the WO3/SiO2 catalyst, are captured. Finally, a possible mechanism for the ODS of bulky organic sulfides using the WO3/SiO2 catalyst is proposed.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139594177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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