Faculty Publications
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Item Potential environmental applications of Helianthus annuus (sunflower) residue-based adsorbents for dye removal in (waste)waters(Elsevier, 2022) Anastopoulos, I.; Giannopoulos, G.; Islam, A.; Ighalo, J.O.; Iwuchukwu, F.U.; Pashalidis, I.; Kalderis, D.; Giannakoudakis, D.A.; Nair, N.; Lima, E.C.Under the framework of Circular Economy, agricultural residues that once were considered an unwanted byproduct, are currently gaining popularity as novel bio-based products for environmental applications. This chapter evaluates the potential of Helianthus annuus (sunflower) biomass residues for (waste)water dye removal considering the factors regulating its subsequent chemical processes and equilibria. The initial pH, which affects both the dye speciation in solution and the surface charge of the adsorbent, is one of the most critical parameters and determines the optimum conditions for efficient dye removal. The soluble dyes, that present a high affinity for water, are generally ionized (e.g., possess positive or negative charge), and therefore, the sorption capacities of an adsorbent are strongly affected by the initial pH of the dye solution. The equilibrium data regarding the removal of various dyes from aqueous solutions using sunflower-based adsorbents (in pristine or chemically modified form) are usually better described by the Langmuir equation; however, in some cases, the Freundlich adsorption model seems to better fit the experimental data. The majority of the kinetic data associated with the removal of dyes using sunflower-based adsorbents follows the pseudo-second-order model. In addition to the thermodynamic adsorption data, this chapter summarizes and discusses also data of desorption experiments performed using dye-loaded adsorbents. © 2022 Elsevier Inc. All rights reserved.Item Enhancing the Dewatering Ability of Sludge by Locally Available Biomass(Springer Nature, 2023) Chopade, G.; Devatha, C.P.In this study, the effect of modified coconut shell biochar is analyzed for its efficacy achievable in sludge dewatering properties. Initially the coconut shell biochar is modified at different molar concentrations of FeCl3, i.e., 1, 2, and up to 5 mol/L, and it is analyzed with different dosages at 0.1, 0.2, and up to 0.4 (g/g of dry solids (DS)) for the improvement in capillary suction time (CST) (s), moisture content reduction (%), filterability (min), and settleability (SV30%) of the sludge. It is found that there is significant decrease in each of these parameters. The optimization study is carried out to optimize the process of sludge conditioning, considering independent regression parameters as dosage (g/g of DS), molarity (M), mixing time (min), and response taken as moisture content (%), the optimum values for the dosage, molarity, mixing time is found to be 0.4 (g/g of DS), 2.5 M and 24.72 min, respectively, with optimized moisture content value of 78% was achieved. Hence, the modified coconut shell biochar can be used as a potential candidate to increase the dewatering ability of the sludge. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023.Item Synthesis of highly-branched alkanes for renewable gasoline(Elsevier B.V., 2020) Mascal, M.; Dutta, S.The gasoline market in the US is nearly twice that of diesel and jet fuel combined, and yet, nearly all research efforts to produce synthetic, biobased fuels center around these latter products. The reason for this is that a major component of gasoline is highly branched alkanes which, unlike straight chained products, are not readily derived from either fatty acid- or carbohydrate-based feedstocks. This review unpacks the motivations behind renewable gasoline synthesis and examines representative approaches to the targeted, de novo synthesis of densely-branched, high-octane isoalkanes and cycloalkanes employing chemocatalytic methods, as contrasted with the catalytic refining of biomass-derived feeds using petrochemical technologies. © 2019 Elsevier B.V.Item Recent advances in the preparation of levulinic esters from biomass-derived furanic and levulinic chemical platforms using heteropoly acid (HPA) catalysts(Elsevier B.V., 2021) Bhat, N.S.; Mal, S.S.; Dutta, S.The esters of biomass-derived levulinic acid (LA) have several potential applications, including cleaner-burning fuel additive, green solvent, fragrance ingredient, and a renewable chemical intermediate for downstream value addition. The levulinic esters (LEs) can be prepared by the acid-catalyzed alcoholysis of the biomass-derived furanic and levulinic chemical platforms such as LA, furfuryl alcohol (FAL), 5-(hydroxymethyl)furfural (HMF), and angelica lactone (AGL). The acid-catalyzed deconstruction of carbohydrates in an alcoholic medium affords the one-pot preparation of LEs. Choosing the right catalyst is of paramount importance for synthesizing LEs from both the economic and environmental perspectives. In this regard, heteropoly acids (HPAs), a class of polyoxometalates (POMs) bearing protons as the counter cation, have found widespread applications as acid catalysts in various organic transformations. HPAs are blessed with conducive properties such as controlled Brønsted and Lewis acidity, high thermal stability, robust structural features, non-toxic nature, tunable solubility, and less corrosiveness. Over the past several years, HPAs have found extensive applications as efficient and environment-friendly catalysts in biorefinery operations, including the synthesis of LEs. At this juncture, it is imperative to ascertain the achievements in this field to date and re-evaluate the challenges. This review attempts to provide up-to-date information about the preparation of LEs using HPA-based catalysts, critically analyze the literature cited, draw conclusions, and propose future prospects. © 2021 Elsevier B.V.Item Synthesis of renewable carbon biorefinery products from susceptor enhanced microwave-assisted pyrolysis of agro-residual waste: A review(Institution of Chemical Engineers, 2022) Rajasekhar Reddy, B.R.; Sridevi, V.; Kumar, T.H.; Sankar Rao, C.S.; Palla, V.C.S.; Suriapparao, D.V.; Undi, G.S.Valuable renewable carbon biorefinery products can be obtained by using agro-residual biomass as a feedstock. Bio-oil, gas, and char products can be obtained from Microwave-assisted pyrolysis (MAP) by converting agro-residual waste. In MAP, the process variables like microwave power, temperature, heating rate, raw materials, susceptors, and catalysts play an important role to alter the product spectrum. The temperature, heating rate, and pyrolysis time can be tuned to obtain the desired products during biomass decomposition. The obtained carbonaceous products can be used as intermediated feedstocks to synthesize a variety of end products. Hence, in this review, the application of MAP for the conversion of agro-residual waste is discussed. Special focus is given to the interaction of microwaves with susceptors. This manuscript provides background, current status, progress, and future scope of MAP technology for waste valorization. The objectives of the review are to address (i) The necessity of environmental protection, (ii) The role of biorefinery in the biomass conversion, (iii) The advancements in the MAP for the resource recovery, (iv) The mechanism of heat generation from microwaves, (v) The effects of process parameters, susceptors, and catalysts in MAP, (vi) The interactions of biomass and susceptors during the pyrolysis, (vii) The formation of valuable renewable carbon products and (viii) The future scope and challenges for the integration of MAP in solid waste management. © 2022 The Institution of Chemical EngineersItem Catalytic synthesis of renewable p-xylene from biomass-derived 2,5-dimethylfuran: a mini review(Springer Science and Business Media Deutschland GmbH, 2023) Dutta, S.; Bhat, N.S.In this work, the renewable synthesis of p-xylene (PX) from biomass-derived carbohydrates has been reviewed. PX is a crucial chemical feedstock and an essential starting material of polyethylene terephthalate (PET). PX can be produced selectively by the Diels-Alder reaction between ethylene and 2,5-dimethylfuran (DMF) followed by catalytic dehydration of the oxanorbornene adduct. DMF is primarily produced by the catalytic hydrogenation of 5-(hydroxymethyl)furfural (HMF), a furanic intermediate produced by the acid-catalyzed hydrolysis/dehydration of biomass-derived hexoses. With ethylene being sourced by dehydrating bioethanol, PET can be made biorenewable in its entirety. The atom economy and carbon efficiency of converting glucose into PX have been calculated. The existing literature (both theoretical and experimental) on the catalytic production of PX from DMF and ethylene are summarized, and future directions on this research have been proposed. The effect of Brønsted and Lewis acidity, porosity, and surface area of the heterogeneous catalysts on the selectivity and yield of PX have been highlighted. In addition, the techno-economic analysis of renewable PET, its future prospects based on the petroleum market, and the possibility of a circular economy of PET using chemical and enzymatic recycling strategies have been discussed. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.Item Recent advances in the production and value addition of selected hydrophobic analogs of biomass-derived 5-(hydroxymethyl)furfural(Springer Science and Business Media Deutschland GmbH, 2023) Anchan, H.N.; Dutta, S.5-(Hydroxymethyl)furfural (HMF), produced by the acid-catalyzed dehydration of biomass-derived hexoses, is a well-recognized renewable chemical intermediate in the biorefinery research for the productions of fuels, chemicals, and materials. However, the inherent hydrophilicity and poor stability of HMF continue to disfavor its production and value addition from an economic standpoint. In this regard, the superior thermal and hydrolytic stability of the hydrophobic analogs of HMF simplify their isolation and purification from the aqueous (or polar) reaction media while enhancing their shelf life. The analogs show promises in supplanting HMF from its derivative chemistry. The halogenated derivatives of HMF, such as 5-(chloromethyl)furfural (CMF) and 5-(bromomethyl)furfural (BMF), can be produced directly from biomass in good isolated yields. The non-halogenated, hydrophobic derivatives of HMF include esters such as 5-(formyloxymethyl)furfural (FMF) and 5-(acetoxymethyl)furfural (AMF), obtained by the dehydration of carbohydrates in suitable carboxylic acids. The ethers of HMF, such as 5-(ethoxymethyl)furfural (EMF), can be produced directly by the acid-catalyzed alcoholysis of biomass. In addition, partially oxidized or reduced derivatives of HMF, such as 2,5-diformylfuran (DFF) and 5-methylfurfural (5MF), have also found significant interests as hydrophobic analogs of HMF. The production and value addition of various lipophilic analogs of HMF are rather scattered in the literature, and no comprehensive review is available in this area to date. This technical review attempts to fill that gap with up-to-date information with a critical analysis of the achievements and challenges. In this review, the production and derivative chemistry of various hydrophobic analogs of HMF have been discussed. The relative advantages and challenges associated with the preparation and value addition of various hydrophobic analogs of HMF are highlighted. Graphical abstract: [Figure not available: see fulltext.]. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.Item Valorization of biomass-derived furfurals: reactivity patterns, synthetic strategies, and applications(Springer Science and Business Media Deutschland GmbH, 2023) Dutta, S.The expertise of synthetic organic chemistry accumulated over the past century has been instrumental in converting biomass to fuels, chemicals, and materials. Particular emphasis has been attributed to using eco-friendly reagents and reaction conditions by adhering to the principles of green chemistry. Catalysis remains at the heart of organic synthesis and has a ubiquitous presence in the organic chemistry literature. Not surprisingly, catalytic processes are increasingly used in the chemistry of renewables under commercially relevant and environmentally acceptable conditions. In this review, the synthesis of various biofuels and renewable chemicals from biomass-derived furfural and 5-(hydroxymethyl)furfural has been elaborated. Synthetic upgrading of furfurals has been shown in the light of chemical modifications of the reactive sites present in them. This review aims to provide a critical understanding of the influence of synthetic organic chemistry in biomass value addition via the furanic platform. This work will encourage the researchers to improve the existing synthetic pathways, develop new synthetic strategies, and broaden the scope of applications for biorenewable products. Graphical abstract: [Figure not available: see fulltext.]. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Item Biological phenol removal using immobilized cells in a pulsed plate bioreactor: Effect of dilution rate and influent phenol concentration(2007) Shetty K, K.V.; Ramanjaneyulu, R.; Srinikethan, G.The continuous aerobic biodegradation of phenol in synthetic wastewater was carried out using Nocardia hydrocarbonoxydans immobilized over glass beads packed between the plates in a pulsed plate bioreactor at a frequency of pulsation of 0.5 s-1 and amplitude of 4.7 cm. The influence of dilution rate and influent phenol concentration on start up and steady state performance of the bioreactor was studied. The time taken to reach steady state has increased with increase in dilution rate and influent phenol concentration. It was found that, as the dilution rate is increased, the percentage degradation has decreased. Steady state percentage degradation was also reduced with increased influent phenol concentration. Almost 100% degradation of 300 and 500 ppm influent phenol could be achieved at a dilution rate of 0.4094 h-1 and more than 99% degradation could be achieved with higher dilution rates. At a higher dilution rate of 1.0235 h-1 and at concentrations of 800 and 900 ppm the percentage degradation has reduced to around 94% and 93%, respectively. The attached biomass dry weight, biofilm thickness and biofilm density at steady state were influenced by influent phenol concentration and dilution rate. © 2007 Elsevier B.V. All rights reserved.Item Studies on exhaust emissions of mahua oil operated compression ignition engine(2009) Kapilan, N.; Reddy, R.P.The world is confronted with fossil fuel depletion and environmental degradation. The energy demand and pollution problems lead to research for an alternative renewable energy sources. Vegetable oils and biodiesel present a very promising alternative fuel to diesel. In this work, an experimental work was carried out to study the feasibility of using raw mahua oil (MO) as a substitute for diesel in dual fuel engine. A single cylinder diesel engine was modified to work in dual fuel mode and liquefied petroleum gas (LPG) was used as primary fuel and mahua oil was used as pilot fuel. The results show that the performance of the dual fuel engine at the injector opening pressure of 220 bar and the advanced injection timing of 30°bTDC results in performance close to diesel base line (DBL) operation and lower smoke and oxides of nitrogen emission.