ORE at CSIR-Institute of Minerals and Materials TechnologyThe ORE digital repository system captures, stores, indexes, preserves, and distributes digital research material.http://ore.immt.res.in:802024-03-25T18:40:45Z2024-03-25T18:40:45ZGreen synthesis of microalgal biomass-silver nanoparticle composite showing antimicrobial activity and heterogenous catalysis of nitrophenol reductionPriyadarshini, SSSethi, SRout, SMishra, PMPradhan, Nhttp://ore.immt.res.in/handle/2018/33992024-02-13T05:18:18Z2023-01-01T00:00:00ZGreen synthesis of microalgal biomass-silver nanoparticle composite showing antimicrobial activity and heterogenous catalysis of nitrophenol reduction
Priyadarshini, SS; Sethi, S; Rout, S; Mishra, PM; Pradhan, N
In this study, we have demonstrated an integrated approach for utilization of microalga Scenedesmus sp. for fabrication of catalytic and antimicrobial silver nanoparticle composite. The algal biomass was harvested from an open raceway pond of 30,000 L scale used for CO2 sequestration. The dried biomass served as a green, nontoxic, reducing and immobilizing agent for synthesis of silver nanoparticles, producing biomass-silver nanoparticle composite. ICP-OES was used to monitor the uptake of silver ions by biomass and subsequent formation of nanoparticles. The composite was calcined at 400 degrees C to fix the nanoparticles and prevent fouling. The calcined biomass-silver nanoparticle (CB-AgNP) composite was characterized using FESEM-EDAX, XRD and TGA. The CB-AgNP composite was used for the first time, as a heterogenous catalyst for reduction of a prominent industrial pollutant, p-nitrophenol. The reduction was carried out in the presence of NaBH4 in aqueous medium under ambient conditions. Batch experiments were conducted to evaluate the effect of calcination temperature, load of material and its reusability, on the catalytic efficiency of material. It was found that as low as 5 mg mL(-1) CB-AgNP material reduced more than 80% and 95% of p-nitrophenol within 1 min and 15 min of exposure, respectively. Rate of PNP reduction was 0.60 mg L-1 min(-1). The composite was easily recovered and reused for continuous batches of p-nitrophenol reduction. The efficiency of catalysis decreased with ten cycles of reuse; however, with an intermittent overnight water wash, the material regained its catalytic activity. Furthermore, the CB-AgNP composite also possessed excellent antimicrobial activity against pathogenic microbes. Two strains each of gram + ve and gram - ve bacteria and three strains of pathogenic fungi were used in the antimicrobial studies using well diffusion method and it was found to be active against all the microbes. The CB-AgNP composite is a potential candidate for a reusable heterogenous catalyst for designing continuous flow system for remediation of industrial effluents rich in p-nitrophenol. Its efficacy against common pathogenic bacteria and fungi can be harnessed for simultaneous antimicrobial treatment of the water. Moreover, this antimicrobial property will further inhibit the biofouling and eventual clogging of the material used in a packed column when used for water treatment.
Department of Science and Technology, Government of India [DST/IS-STAC/CO2-SR-169/13(G)]; DST-UKIERI Award [DST/INT/UK/P-128/2016]; Council of Scientific and Industrial Research, Govt. of India [20/12/2015 (ii) EU-V]
2023-01-01T00:00:00ZTungsten and molybdenum based polyoxometalates for photo and electrocatalytic carbon dioxide conversion - A critical reviewBhatt, SSaha, Shttp://ore.immt.res.in/handle/2018/33982024-02-13T05:18:18Z2023-01-01T00:00:00ZTungsten and molybdenum based polyoxometalates for photo and electrocatalytic carbon dioxide conversion - A critical review
Bhatt, S; Saha, S
Today, carbon dioxide (CO2) is one of the most pervasive greenhouse gases in the atmosphere, mainly because of the burning of fossil fuels. The carbon dioxide reduction reaction by photocatalysis and electrocatalysis is one approach that holds a lot of promise for easing the global crisis on the environmental and energy fronts. Developing and constructing high-performance photo-and electrocatalysts is a challenge that is being studied. The class of anionic metal-oxo clusters known as polyoxometalates (POMs) brings diverse and interesting chemical and physical characteristics that can be modified easily. The studies reveal that POMs are emerging to be distinctive photo/electrocatalysts for these reactions because of their unmatched advantages, like thermal and redox stability, light-absorbing capacity, quasi-semiconductor properties, etc. Numerous studies have demonstrated the capability of tungsten and molybdenum-based photo-and electrocatalysts for CO2 reduction and conversion into value-added products. This review has covered the most recent developments in tungsten and molybdenum-based POMs that convert CO2 into multiple products (CO, H2, HCOOH, HCHO, CH3OH, etc.). Perspectives for designing and constructing different kinds of POM-based catalytic systems have been offered.
CSIR-Institute of Minerals & Materials Technology, Bhubaneswar, India [CSIR-IMMT-OLP-112]
2023-01-01T00:00:00ZStudies on low-grade coking coal characterisation, flotation response and process optimisationHazare, GPradhan, SSDash, NDwari, RKhttp://ore.immt.res.in/handle/2018/33962024-02-13T05:18:17Z2023-01-01T00:00:00ZStudies on low-grade coking coal characterisation, flotation response and process optimisation
Hazare, G; Pradhan, SS; Dash, N; Dwari, RK
The work illustrates the physico-chemical, petrographic characteristics and flotation response of low-grade oxidized coking coal containing 39.5% ash. The maceral composition, surface oxidation, and particle liberation are the factors that affect coal flotation. The oxidized coal requires more collectors than the freshly ground coal. The flotation process modeling and optimization of -0.5 mm coal fraction was carried out using response methodology and central composite rotatable design (CCRD). The diesel, MIBC, and sodium hexametaphosphate are used as collectors, frothers, and depressants to maximize the coal grade, yield, and combustible recovery. At an optimum dosage of 1.35 kg/ton collector, 0.2 kg/ton frother, and 0.5 kg/ton depressant, it is possible to achieve 11.3% ash-clean coal with a 50.72% yield from 39% feed ash coal. The ash, yield, and combustible recovery model prediction matched well with the experimental results. The R-2 of the ash, yield and combustible recovery model are 0.9676, 0.9662, and 0.9692, respectively. The work highlights that Indian coal can upgrade for metallurgical use using a flotation process.
Ministry of Steel, Government of India; [GAP 306]
2023-01-01T00:00:00ZImproved damping behavior of squeeze-cast AZ91-Ca-Sb magnesium alloy with nano-SiC particles additionsGanguly, SMondal, AKhttp://ore.immt.res.in/handle/2018/33952024-02-13T05:18:17Z2023-01-01T00:00:00ZImproved damping behavior of squeeze-cast AZ91-Ca-Sb magnesium alloy with nano-SiC particles additions
Ganguly, S; Mondal, AK
The damping behavior of the SiCnp reinforced AZ91 + 2.0Ca+ 0.3Sb (wt%) alloy in the temperature range of 25-350 degrees C and at frequencies of 1, 5, and 10 Hz has been evaluated. All the AZ91 + 2.0Ca+ 0.3Sb+xSiCnp [x = 0.5, 1.0, and 2.0 (wt%)] nanocomposites exhibit higher storage modulus, loss modulus, and damping capacity than the alloy. The storage modulus decreases with an increase in temperature and frequency, whereas the loss modulus and damping capacity increase with an increase in temperature and decrease with frequency. The nanocomposites display a higher dislocation density and activation energy than the alloy, and the values are the maximum in the nanocomposite with 2.0SiCnp. The higher damping response of the nanocomposites is due to the presence of nano-SiC particles, higher storage and loss moduli, higher activation energy, and increased dislocation density. The Granato-Lucke mechanism, grain boundary or viscous damping, and dislocation damping are the operative damping mechanisms in the alloy and all the nanocomposites.
Indian Institute of Technology (BHU) Varanasi, India [IIT (BHU)/R D/SM/2018-19/4530/L]
2023-01-01T00:00:00Z