SrTiO 3 nanocube and three dimensional, mesoporous BiOBr catalysts were synthesized by sol-gel and precipitation methods respectively. Various weight percentages of SrTiO 3 -BiOBr heterojunction composite catalysts (x% SrTiO 3 -BiOBr where x = 5, 10, 30, 50 & 70 percentage of SrTiO 3 ) were synthesized by impregnation method. All the synthesized catalysts were characterized by various instrumental techniques. The results of PL and EIS indicate that the heterojunction catalyst, 10% SrTiO 3 -BiOBr (10-ST/BB), has the lowest recombination rate of e − - h + pairs and the lowest electron transfer resistance respectively. Photocatalytic activities of the synthesized catalysts were tested towards the degradation of carcinogenic reactive dyes such as reactive blue 198, reactive black 5 and reactive yellow 145 in presence of visible and solar irradiations. Among the catalysts 10-ST/BB resulted in the highest photocatalytic activity towards the degradation of all the three dyes. Kinetics studies on degradation indicated that it followed pseudo first order. The efficiency of dye degradation was found to be better in the presence of solar light than under visible light degradation due to ≃ 4% UV light in solar irradiation. TOC, HPLC and COD studies confirm that the dyes are mineralized into some organic salts such as acetates, formates, etc., CO 2 , water and salts.

Photocatalytic activities of novel SrTiO3 – BiOBr heterojunction catalysts towards the degradation of reactive dyes

Research development of processes for refining bio-oils is becoming increasingly popular. One issue that these processes possess is their high requirement for H2 gas. In response, researchers must develop catalysts that perform deoxygenation while minimizing H2 consumption-selective deoxygenation. Unlike traditional deoxygenation processes, selective deoxygenation reactions and catalysts represent an information gap that, prior to this publication, has yet to be reviewed. This review addresses the gap by providing both a summary of recent research developments and insight into future developments of new catalytic materials. Bifunctional catalysts containing a combination of oxophilicity and an active metal phase appear to be the most beneficial for selective deoxygenation processes in a H2 -modest environment. It is important that catalysts have a supply of disassociated hydrogen, because without such, activity and stability will suffer. The authors recommend to maximize the use of internally available hydrogen in bio-fuel, which may be the only viable approach for deoxygenation if external H2 gas is limited. This would be possible through the development of catalysts that promote both the water-gas-shift and deoxygenation reactions.

Selective Deoxygenation of Biomass-Derived Bio-oils within Hydrogen-Modest Environments: A Review and New Insights.

This article reviews the recent advances in the development of zeolite catalysts for biomass valorization processes to produce both biofuels and/or bio-based chemicals, which is an emerging and fast expanding field. The work deals with different types of feedstocks, including vegetable oils, lignocellulose and sugars, as well as with a number of relevant intermediates and platform molecules. Transformation of biomass into valuable products is hindered by a number of factors, mainly related to its complex composition, as biomass typically consists of bulky molecules with high oxygen content. Accordingly, biomass processing usually requires the combination of multiple steps and severe conditions, hence concepts like atom efficiency, product selectivity, and catalyst deactivation become of special relevance. A great progress has been achieved in the past years engineering the properties of zeolites for being adapted to the challenges associated to biomass valorization. The possibility of tailoring th...

Progress in the design of zeolite catalysts for biomass conversion into biofuels and bio-based chemicals

Herein, we report the synthesis of nitrogen and sulphur co-doped TiO2/rGO nano composites (NST/x%-rGO, x = 2.5, 5, 7.5 & 10%) by facile single step hydrothermal method. The structural and morphological analyses of the synthesized composites were made by XRD, IR, XPS, SEM and TEM, while optical properties were studied by Raman and DRS-UV spectrophotometric techniques. Charge separation efficiency and the extent of recombination were investigated by EIS and photoluminescence (PL) studies. Photodegradation efficiency was evaluated by the de-colorization of congo red (CR), methylene blue (MB) and reactive orange 16 (RO16) dyes. For comparison purpose, TiO2/rGO (GT) and nitrogen, sulphur co-doped TiO2 (NST) were also synthesized, characterized and their photocatalytic activities were evaluated and compared. NST/5%-rGO exhibited the highest photocatalytic activity towards the degradation of all the three dyes under visible light. Improved optical absorption property and increased life time of the photogenerated charge carriers have been observed. Trapping experiments with different quenchers suggested that superoxide radicals (O2 −) were highly responsible for the degradation process compared to other species such as hydroxyl radicals (OH ) and photogenerated holes (h+).

Visible active N, S co-doped TiO2/graphene photocatalysts for the degradation of hazardous dyes

A series of Pt/SAPO-11 catalysts were prepared with various Si/Al ratios and Pt loadings and characterized by using BET, XRD, XRF, and CO pulse adsorption, as well as 29Si NMR and NH 3 -TPD techniques. Their catalytic performances in hydroconversion of Jatropha oil were tested with a fixed-bed flow reactor system. The isomerization activity increased with the Si/Al ratio because there were more medium acidic sites on the SAPO-11 supports. Pt/SAPO-11 catalysts with a Si/Al ratio of 0.4 demonstrated high activity for both deoxygenation and isomerization among catalysts with the same Pt loading. The deoxygenation, isomerization and cracking activities strongly depended on the Pt loading. The best activity was observed for the sample with a 3 wt% Pt loading, which generated an 83% yield of iso -C15-18 hydrocarbons under the LHSV of 0.5 h −1 . Based on the mechanistic study of hydroconversion of methyl oleate, a reaction network for the hydroconversion of Jatropha oil was suggested.

Effects of Si/Al ratio and Pt loading on Pt/SAPO-11 catalysts in hydroconversion of Jatropha oil

Biofuels, the hydrocarbons less than C 18 , produced by catalytic cracking of nonedible vegetable oils are the potential source to battle energy demand and pollution. Among the non edible oils, jatropha is the apt candidate for the production of biofuel. Jatropha oil can be cracked catalytically over solid acid catalysts to yield liquid fuels with superior characteristics. We present here the hydrothermal syntheses of a microporous solid acid catalyst (HZSM-5 with Si/Al = 14), mesoporous materials (AlMCM-41) with varying Si/Al ratios (Si/Al = 18, 41, 72 and 95) and composite catalyst comprising HZSM-5 (as core) and varying coating percentages (5, 10 and 20%) of AlMCM-41 (as shell). All the synthesized catalysts were characterized by using XRD, BET N 2 sorption studies, ICP, TPD and SEM techniques. Herein we report the catalytic activities of all the synthesized catalysts towards the cracking of jatropha oil obtained at the optimized conditions of temperature – 400 °C, WHSV – 4.6 h −1 and reaction time – 1 h. Of all the mesoporous catalysts with varying Si/Al ratios, AlMCM-41 (Si/Al = 18) was found to be the most active catalyst as it converted 65% of jatropha oil yielding 39% of bioliquid fuel with 47% and 36% selectivities towards green diesel and green gasoline respectively. In the core–shell architecture of the composite catalyst, different % coatings of the best active mesoporous material (AlMCM-41, Si/Al = 18) over the best active microporous material (ZSM-5, Si/Al = 14) were done. AlMCM-41/ZSM-5 (25, 15, 10) showed remarkable performance in the conversion of jatropha oil (99%) yielding 70% of bioliquid fuel with very high selectivity (61%) towards green gasoline.

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Liquid hydrocarbon fuels from jatropha oil through catalytic cracking technology using AlMCM-41/ZSM-5 composite catalysts

Photocatalytic activity of multielement doped TiO2 in the degradation of congo red

A greener water treatment technique is required to eliminate the hazardous and carcinogenic chemicals such as pesticides, insecticides, etc from contaminated water. Photocatalysis based on titania are the excellent materials to achieve complete degradation of the agro chemicals. In this work, nanocrystalline titania and strontium titanate have been synthesized by sol-gel process. Doping of titania based catalysts with metal or non-metal elements decreases the bandgap and hence increases the photo efficiency. Synthesized titania and strontium titanate have been doped by multielements (C, N, B, F) and Ni/Ru respectively. The catalysts have been characterized by XRD, UV-DRS, SEM and TEM. The synthesized catalysts have been tested for their catalytic activity towards the degradation of carcinogenic insecticide imidacloprid using multilamp photo reactor. The reaction parameters such as initial concentration of insecticide, catalyst weight and pH have been optimized and the results were discussed.

Synthesis, Characterization and Catalytic Activities of Titania based Nanocatalysts for the Degradation of Carcinogenic Imidacloprid

Synthesis, characterization and photocatalytic activity of potassium Titanate nanocatalyst

_ Abstract: Alpha amylase and alpha glucosidase inhibition were investigated in this in vitro investigation utilising ethanoic extract of the leaves of Sesbania grandiflora , Moringa oleifera , Solanum nigrum , and Spinacia oleracea . The inhibition of alpha amylase was seen for Moringa oleifera (82.9 %), Sesbania grandiflora (80.48 %), Spinacia oleracea (80.48 %) and Solanum nigrum (76.42 %), from their respective ethanolic extracts, when compared to the reference medication acarbose (89.43 %). Sesbania grandiflora (69.49%), Moringa oleifera (83.15%), Solanum nigrum (66.10%), and Spinacia oleracea (66.94%) all inhibited alpha glucosidase at a concentration of 100 µg/ml, whereas the standard acarbose medication inhibited alpha glucosidase at 89.83%. The ethanolic extract of leaves from herbs is thus proposed as a possible source for natural antidiabetic and antioxidant chemicals with use in the treatment of diabetes mellitus.

J. Amala Infant Joice

Papers

Liquid hydrocarbon fuels from jatropha oil through catalytic cracking technology using AlMCM-41/ZSM-5 composite catalysts

Photocatalytic activity of multielement doped TiO2 in the degradation of congo red

Synthesis, Characterization and Catalytic Activities of Titania based Nanocatalysts for the Degradation of Carcinogenic Imidacloprid

Synthesis, characterization and photocatalytic activity of potassium Titanate nanocatalyst

In Vitro Alpha Amylase and Alpha Glucosidase Inhibitory Activity of Important Lettuces from South Indian Region