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Coal and coal-based products (by-products), along with other fossil fuels should be used with caution because of their impact on human health and the global climate. In the light of the environmental impact these fossil fuels cause, it's essential to understand the elemental configuration of coal-derived samples and their impact on the ecosystem. Some reports in past have described, geochemical and mineralogical physiognomies of fly-ash and their impact on the environment. However, a comprehensive investigation of various aspects of fly ash like geochemistry, mineralogy, morphology, and toxicological effects has been very sparse and the present study reports the above aspects. The ICP-OES studies confirm the presence of various elements (Al, Ca, Fe, Mg, Na, P, S, Si, and Ti) in the samples. The XRD analysis exposed the presence of minerals like Quartz, H-Hematite, Anatase, Muscovite, and Rutile, in addition to the various phases such as amorphous and crystalline in the fly-ash. Specific samples also possessed Ilmenite which is uncommon in many other samples. Chromium and lead, the well-known heavy metals to cause soil and water pollution in the neighbourhood were found to be existing in higher concentrations in the fly-ash samples, whereas cadmium was found to be the least among the toxic elements found in the samples. The samples were subjected to FE-SEM analysis, which reveals the presence of irregularly shaped minerals and unburnt carbon known to reduce the burning efficiency of coal, especially in power plants. Toxicology studies reported in the work suggested that fly-ash is toxic to the environment at higher concentrations than at lower concentrations.

A series of silica doped alumina (SDA) [Si-Al2O3] having high surface area and narrow pore size distribution are synthesized with varying amount of silica and used as a support material to facilitate incorporation of Co, Mg and Zr into it. These supported Co-Mg-Zr/SDA materials are used as catalysts for selective synthesis of middle distillate through Fischer-Tropsch synthesis (FTS) reaction. Trace quantity (∼0.05 wt %) of ruthenium (Ru) has also been used as a promoter for Co -Mg-Zr/SDA catalyst to improve the reducibility, selectivity towards middle distillate and increasing the catalyst life. The detail characterizations of catalysts indicate that Ru promotion and narrow pore size distribution facilitate CO conversion and middle distillate selectivity. Synthetic syngas of composition (H2 = 28.63%, CO = 14.27%, CO2 = 9.25%, CH4 = 1.0%, and N2 = 46.85%), which may be obtained after coal gasification and H2 enrichment process by water gas shift (WGS) reaction has been used as a reactant for middle distillate synthesis. The role of Ru and silica proportion on Co-Mg-Zr/SDA is investigated through Low Temperature Fischer-Tropsch (LTFT) synthesis at 220 °C temperature and 30 bar pressure. The surface acidity of the Ru/Co-Mg-Zr/SDA catalyst plays an important role for middle distillate selectivity and CO conversion. To determine the durability of catalysts, 300 h continuous experimental run has been conducted at Gas Hourly Space Velocity (GHSV) of 500 h−1. Among the catalysts in the present study, Ru/Co-Mg-Zr/SDA(7.5) catalyst shows highest CO conversion (94.2%) with 85% selectivity of C6-C19 hydrocarbon.

Biochar fuel (CH0.50O0.19N0.06) was prepared from Leucaena leucocephala bark (CH2.80O0.53N0.03) through the slow pyrolysis process adopting design of experiments technique. Modelling and optimization of the slow pyrolysis process was respectively carried out implementing five level central composite design and numerical technique under response surface methodology. Pyrolysis temperature and time were taken as independent parameters while biochar fuel yield, bulk density, higher heating value, energy density and energy yield were chosen as dependent parameters. The optimal pyrolysis temperature and time were estimated to be 367.47 °C and 135.38 min respectively. These optimum values of temperature and time gave biochar yield 47.29%, bulk density 319.73 kg/m3, higher heating value 23.30 MJ/kg, energy density 1.21, and energy yield 56.55%. The developed quadratic models were checked using ANOVA (analysis of variance) technique for their validity and degree of fitness. The high values of ‘Adequate precision’,R2 and its negligible difference with ‘AdjustedR2’ as well as ‘PredictedR2’ for each model indicated that the fitted empirical models can be used for prediction with reasonable precision. The quadratic models revealed strong interaction between pyrolysis temperature and time towards preparation of biochar fuel. It was further observed that desirability of pyrolysis temperature (0.91) is more than pyrolysis time (0.63). Comparison of Van Krevelen diagram of present biochar fuel with several other biochar fuels and coals showed that prepared biochar has better fuel properties in comparison to raw bark.

Meeting the ever-growing demand of global energy in an eco-friendly manner necessitates the evaluation of coal and its combustion residues. For management of coal combustion and its residues on sustainable basis, characterization of trace elements and polycyclic aromatic hydrocarbons (PAHs) is imperative. The feed coal, fly ash, and bottom ash from a power plant (Unchahar, India) were evaluated. Feed coal is low grade high volatile sub-bituminous. Quartz and kaolinite are the predominant minerals in the coal, whereas quartz, mullite, and anhydrite in the ashes. Si > Al > Fe > Ca are the major elements in coal and it ashes. As compared to coal, most of the elements are enriched in the ashes; especially As, Cu, Ni, Pb, and Zn are highly enriched (enrichment factor > 5.0) in fly ash. Cluster analysis showed that As, Co, and Cd are associated with the ash forming elements like P–Mg–Ca–S; Ni, V, Cu, Pb, Zn, and Cr with Al-silicate minerals. Leaching study revealed that the trace elements are within the permissible limits for industrial effluents. The total PAHs content was much higher in coal (4542 μg kg −1 ) than fly ash (32.4 μg kg −1 ) and bottom ash (10.1 μg kg −1 ). High molecular weight PAHs were predominant in coal and fly ash, low molecular weight PAHs in bottom ash.

A simple and one pot process for the synthesis of flavanones in the presence of SO 4 2 - / ZrO 2 , a reusable, heterogeneous catalyst has been described. The reactions were conducted both with and without solvent (using toluene as solvent) at 140 °C with reaction times of 3–4 h. Under these conditions several examples were found with very good yields (73–87%) and up to 83% selectivity. The catalyst was easily recycled and reused without loss of its catalytic activity. The present synthetic method is a simple, clean and environment friendly alternative for synthesizing substituted flavanones.

Air is a very essential part for the existence of humans and other living organisms. To know the quantum of atmospheric dust fall and their mineral and morphological characteristics, dust samples were collected at monthly intervals from three different sites (commercial, residential, and control) of the Jharia coal mining area, India. Samples were analysed for heavy metals, minerals, and morphological features by ICP-AES, XRD, and SEM respectively. The yearly average dust fall was higher for the commercial site (15.5 t/km2/month) than the residential site (10.7 t/km2/month) of Jharia coal mining area. The dust deposition rate was highest during summer (March–June), followed by winter (October–February) and lowest in the monsoon season (July–September). The elemental fall was higher for Zn followed by Pb > Sr > Cu > V > Cr > Ni > Co. The major minerals in dusts from Jharia mining area were quartz, kaolinite, pyrite, albite, and magnesiohornblende. The SEM-EDS analysis showed the dust in commercial sites has contributions from coal, and soil. In the residential site, soot particles from domestic coal burning; and in control site, soot particles from biomass burning were observed in SEM. Overall the intensity of dust pollution is more in the commercial sites of the coal mining area.

Atom efficient synthesis of various value added products has been focused as an intense research area after Kyoto protocol. Styrene epoxidation is a challenging reaction as styrene epoxide is an important monomer for large number of polymers. It has been found that surface acidity and redox property of the catalyst has a major contribution to the catalytic activity for oxidation reaction. In this study Co-HMS-X catalyst was prepared and characterized by BET surface area and porosity measurement, SAXS, SANS, FESEM, HRTEM, UV–vis spectra, FTIR, 29Si NMR, H2-TPR and NH3-TPD techniques. It is observed that 5 mol% Co-HMS-X showed highest catalytic activity for styrene epoxidation reaction using molecular O2 as an oxidant. Interestingly it is found that among three different dopant (Al, Ga, Tl), the Ga promoted Co-HMS-X catalyst (Si:Co:Ga = 100:5:1.25) showed highest catalytic activity in terms of styrene conversion (100%) and styrene epoxide selectivity (68%). The unusual trend of Al, Ga and Tl towards the activity of Co-HMS-X (5 mol%) catalyst has been discussed from the results obtained in the H2-TPR and NH3-TPD study.

An integrated membrane system for crystallization has been studied experimentally. Performance of two membrane based processes; Osmotic Crystallization (OC) and Ultrafiltration (UF) were compared by using different membrane configurations (flat sheet and hollow fibre). Possibility of reduction in crystallization time by antisolvent addition was also explored. Different process combinations were developed for comparative performance analysis. For macromolecular feeds, it was seen UF see was more viable; though FO was attractive with respective to operation at ambient temperature and pressure. Integrated membrane based antisolvent crystallization did not affect the purity of the crystals as is evident from the X-Ray Diffraction analysis of the obtained crystals. The integrated membrane system showed an energy saving of 33.33% while antisolvent addition decreased energy consumption by 16.7%. Combination of membrane based and antisolvent crystallization further lowered the energy consumption by a whopping 36%. This was accompanied with a proportional reduction of 17% of crystallization time with respect to conventional evaporative crystallization. The competitive flux and energy saving quotient makes the system techno-economically viable.

The synthesis of e-caprolactam, a demanding monomer, through a heterogeneous catalytic pathway has remained a key area of research in the last decade. The Beckmann rearrangement reaction in the vapor phase using a solid acid catalyst was found to be very effective for producing e-caprolactam. It is observed that niobium incorporated into mesoporous silica serves as a good catalyst for the Beckmann rearrangement reaction. Recently developed mesoporous silica, having an ordered honeycomb structure, is very useful as it can lead to effective diffusion of reactants and products for several reactions. In this study, Nb-doped mesoporous HMS-X nanocomposite materials with different Nb loadings were prepared by a one step hydrothermal synthesis and characterized by BET surface area and porosity measurements, wide and small angle XRD, SEM, HR-TEM, elemental mapping, FTIR, 29Si-NMR and NH3-TPD techniques. The activity of the Nb–HMS-X catalyst was evaluated for the vapour phase Beckmann rearrangement reaction. The catalyst characterization study shows that Nb is highly dispersed on the HMS-X matrix at lower Nb loadings. At higher Nb loadings it is present in the extra-framework position as revealed from XRD, HR-TEM and 29Si-NMR studies. The NH3-TPD result shows the presence of acidic sites on the catalyst surface, which are active sites for the Beckmann rearrangement reaction. Using the Nb–HMS-X catalyst (Si/Nb = 13) under vapour-phase reaction conditions [temperature = 350 °C, weight hourly space velocity (WHSV) = 15 h−1, cyclohexanone oxime in benzene, cyclohexanone oxime : benzene weight ratio of 1 : 11] gave 100% cyclohexanone oxime conversion with 100% e-caprolactam selectivity, with a space time yield of 1.4–1.6 × 10−3 mol h−1 gcat−1. The catalyst was highly recyclable up to 9 times without significant loss of catalytic activity.

In this decade intensive research was carried out to prepare mesoporous non-silicious oxide for various application. Development of mesoporous ceria based material has become most important because of its application in catalysis, solar cell and photovoltic cell. The selective aerobic oxidation of primary alcohols through an environment benign route to synthesize aldehydes is of utmost importance. The catalytic role of supported gold nanoparticles for aerobic oxidation reaction has been focused in the era of sustainable chemistry. The unique redox property of ceria is a fascination for developing Au–CeO2 catalyst in many studies on aerobic oxidation reaction. In this work, we have prepared mesoporous manganese doped ceria to examine the change of physicochemical properties due to incorporation of managnese to the ceria lattice. Deposition of gold nanoparticles and Mn-doping on ceria enhanced the redox behaviour of ceria as well as the basic properties. A thorough characterization by BET S.A., XRD, Raman, HRTEM, STEM, H2-TPR, CO2-TPD, XPS, XAFS reveal the distortion of in the doped CeO2 lattice is electronic in nature rather than structural distortion. The catalytic activity of the catalysts demonstrate the promotional role of gold nanoparticle in this study.

Hydrogen is considered as the fuel for next generation and extensive research is being pursued for search of new techniques for hydrogen production from renewable sources. There is a diverse collection of hydrogen production processes at their different stages of development. This review paper analyzes the industrial and emerging hydrogen production technologies. These processes include steam methane reformation, partial oxidation, autothermal reforming, steam iron, plasma reforming, thermochemical water splitting and biological processes. Till date, steam reformation of methane is the most used industrial technique and its efficiency can go up to 85%. It meets up to 50% of total hydrogen consumption in the world. Continuous research is going on to enhance production yield as well as to improve the process economics. Considerable work is going on about sorption enhanced reforming and membrane reactor for this purpose. Partial oxidation and autothermal reforming processes are the other two processes which are also used for industrial. The most sought process is the thermochemical water splitting using sunlight. Several research institutes are engaged in the development of hydrogen production technologies using renewable sources. Plasma reformation and biological processes are intensively worked out throughout the globe. The present article reviews the recent developments in industrial techniques which will lead to enhancement of hydrogen production. The non-conventional techniques are described in this article as emerging techniques, which are the promising approaches for hydrogen production from biomass, an abundant, clean and renewable source.

Temperature-programmed reduction (TPR) and temperature-programmed desorption (TPD) were used to study the effects of Cu and Ca promotion on Fe–Zn-based Fischer–Tropsch catalysts. The reduction temperature for Fe2O3 → Fe3O4 was unaffected by Ca addition but decreased when promoted with Cu. Fe–Zn promoted with Cu and Ca showed even much lower reduction temperature for Fe2O3 → Fe3O4. Ca promotion enhances carburization and increases surface acidity and basicity of the Fe–Zn oxide precursor. While Cu inhibits carburization and decreases the surface acidity and basicity of the Fe–Zn oxide precursor. The implications of these effects on the application of catalysts for FT are discussed.

An efficient protocol for synthesis of 3,3′-diindolylmethanes using recyclable Fe-pillared interlayered clay (Fe-PILC) catalyst under aqueous medium has been developed. All synthesized 3,3′-diindolylmethanes showed promising antileishmanial activity against Leishmania donovani promastigotes as well as axenic amastigotes. Structure–activity relationship analysis revealed that nitroaryl substituted diindolylmethanes showed potent antileishmanial activity. The 4-nitrophenyl linked 3,3′-diindolylmethane 8g was found to be the most potent antileishmanial analog showing IC50 values of 7.88 and 8.37 μM against both L. donovani promastigotes and amastigotes, respectively. Further, a pharmacophore based QSAR model was established to understand the crucial molecular features of 3,3′-diindolylmethanes essential for potent antileishmanial activity. These compounds also exhibited promising antifungal activity against Cryptococcus neoformans, wherein fluorophenyl substituted 3,3′-diindolylmethanes were found to be most potent antifungal agents. Developed synthetic protocol will be useful for economical and eco-friendly synthesis of potent antileishmanial and antifungal 3,3′-diindolylmethane class of compounds.

The present research work is intended to synthesize a series of substituted 2,3-dihydro-2-phenylquinazolin-4(1H)-ones using clay-supported heteropolyacid as a novel heterogeneous, reusable and inexpensive catalyst. This catalyst afforded excellent yields in very short reaction times that shows high selectivity without affecting other functional groups, such as carbon–carbon double bond and heterocyclic moieties. The catalyst could be recycled at least six times and reused. The synthesis involves cyclo-condensation of anthranilamide with an aldehyde at room temperature in the presence of small amount of the catalyst. No column purification is required and products can be purified by simple crystallization.

Supported gold nanoparticles perform as a potential catalyst for CO oxidation, propylene epoxidation and hydrogenation reactions, while using them for alcohol oxidation reaction in the presence of molecular oxygen is a challenging task. Nanocrystalline ceria supported gold catalysts are suitable candidates for alcohol oxidation reaction under mild condition. In this study, ceria based mixed oxides were prepared by modified sol–gel method using triethanolamine/water mixture where the defect sites were created by doping Sm3+ cation to cerium oxide. The catalysts were characterized by XRD, FT-RAMAN, TPR, TPD, XPS, XAFS, and HRTEM techniques. Strong gold–support interaction facilitates the easy removal of capping oxygen ions present in the Sm3+ doped cerium oxide surface as observed by XPS and TPR studies. The acid–base property of the CeO2 oxide after incorporation of samarium and gold deposition was observed from TPD studies. The Au/Sm-CeO2 catalyst was active for benzyl alcohol oxidation reaction using molecular O2 under mild condition.

Isolongifolene and various other isolongifolene-based products are commercially important chemicals that find applications in perfumery and fragrance industry. These important commodity chemicals are generally prepared by homogeneous catalyzed reactions of longifolene in liquid phase. In the present study, role of acidity and acid distribution on montmorillonite, pillared interlayered clay and modified pillared clay catalysts have been studied for the first time in vapor phase system for the conversion of longifolene to isolongifolene. The number and strength of acid sites of montmorillonite clay mineral have been modified by steps of synthesis and by cations selection. Reaction of Al- pillared montmorillonite with Ru 3+ yielded a catalyst with significantly higher distribution of weak acid sites while fortification of montmorillonite with Ce 3+ and La 3+ had little effect on total acidity and its distribution. In the present study, an attempt has been made to correlate the activity of the catalysts with total acidity, number and strength of the acid for the conversion of longifolene to isolongifolene. NH 3 TPD determined the concentration and strength of acid sites.

Stern standards on the quality of hydrocarbon fuels, particularly on sulphur and aromatic content, is one of the major drivers of increasing hydrogen demand by petroleum refineries. The fuel standards are often predicated on reducing environmental pollution. However, most commercial hydrogen production processes are based on non-renewable resources which are associated with high carbon footprints. With increasing demand of hydrogen, the carbon footprint associated with hydrogen production will increase accordingly. Incentives for green hydrogen production technologies will be an impetus toward smooth succession of industrial processes from high to low carbon footprint. It will engender a shortened learning curve and facilitate entry of green reforming technologies into the hydrogen market. This review examines the potential of some emerging reforming technologies for hydrogen production from renewable resources.