Falguni Pattnaik

Bio: Falguni Pattnaik is an academic researcher from Indian Institute of Technology Delhi. The author has contributed to research in topics: Hemicellulose & Biofuel. The author has an hindex of 4, co-authored 8 publications receiving 51 citations. Previous affiliations of Falguni Pattnaik include University of Saskatchewan.

Biofuels from agricultural wastes

Abstract: To overcome the current energy crisis and deterioration of environmental conditions, production of fuel from sustainable and renewable sources is the major goal for an energy-demanding society. Agricultural wastes are a major fraction (1.5×1011 tons/annum) of lignocellulose biomass and this resource can be utilized as feedstock for generation of biofuels (bioethanol, biobutanol, biogas, biohydrogen, and biodiesel). Agricultural wastes do not only include residues from cultivation but also waste generated from processing of agro products, managing livestock, and distribution of fruits and vegetables. This chapter outlines the classification of agricultural wastes, its compositions, and different processing and biofuel production routes. In the chapter a major emphasis is given to the biochemical routes for biofuel production.

Subcritical water hydrolysis of Phragmites for sugar extraction and catalytic conversion to platform chemicals

Abstract: Phragmites karka, also known as common reed, is a perennial grass and a highly invasive crop species, which creates ecological problems by competing with native biodiversity and vegetation. This study involves subcritical water hydrolysis of Phragmites to produce monomeric sugars followed by the catalytic conversion of the sugar-rich hydrolysate to furfural and levulinic acid. Subcritical water hydrolysis was performed by the Central Composite Design method at variable temperatures (150–230 °C), reaction time (15–60 min) and feed concentration (2–5 wt%). The temperature was found to be the most prominent factor affecting biomass hydrolysis. The yield of total reducing sugars from biomass hydrolysis was in the range of 2.1–18.1% where the highest yield was obtained at the optimal temperature (190 °C), reaction time (37.5 min) and feed concentration (2 wt%). During subcritical water hydrolysis of Phragmites, two main degradation products obtained at a higher temperature (230 °C) and reaction time (37.5 min) were furfural (8.2%) and 5-hydroxymethylfurfural (11.7%). However, at 230 °C and a longer reaction time of 60 min, 5-hydroxymethylfurfural yield reduced to 5.1% owing to its conversion to humin while furfural yield elevated to 9.9%. Catalysts such as ZrO2, TiO2, Zr0.5Ti0.5O2, WO3–ZrO2, WO3–TiO2 and WO3–Zr0.5Ti0.5O2 were involved in the conversion of the sugar-rich hydrolysate obtained from subcritical water hydrolysis of Phragmites. The highest sugar conversion was found to be 92% with WO3–ZrO2 resulting in the yields of furfural (51%) and levulinic acid (34%). The activity of particular catalysts (e.g. WO3–ZrO2, WO3–TiO2 and WO3–Zr0.5Ti0.5O2) relied on the synergistic effects of Lewis and Bronsted acid sites.

Catalytic conversion of lignocellulosic polysaccharides to commodity biochemicals: a review

Abstract: The applications of green chemistry and industrial bioprocessing are becoming more popular to address concerns of pollution, climate change, global warming, circular bioeconomy, sustainable development goals and energy security. Both biological and thermochemical routes can play vital roles in transforming waste lignocellulosic biomass to high-value bioproducts. Lignocellulosic biomass contains essential building blocks that could be tapped to generate biofuels, biochemicals and biomaterials to replace petroleum-derived fuels and chemicals. Besides containing extractives and ash, lignocellulosic feedstocks are made up of cellulose, hemicellulose and lignin typically in the ranges of 35–55 wt%, 20–40 wt% and 10–25 wt%, respectively. Catalytic thermochemical approaches are effective for biomass conversion with a significant yield of various platform chemicals, such as furfural, 5-hydroxymethylfurfural, levulinic acid and other furan or non-furan-based chemicals. These chemicals play a crucial part in the synthesis of different fuel-based materials, which can successfully replace petroleum-based chemicals or fuels. Lignocellulosic biomass and their derived monomeric sugars can be catalytically converted into various platform chemicals using different homogeneous and heterogeneous catalysts. In this review paper, we have highlighted some promising catalysts such as mineral acids, mesoporous silica materials, zeolites, metal–organic frameworks, metal oxides and ionic liquids used in biorefining to generate biochemicals. We have also reviewed a few pieces of notable literature presenting the catalytic conversion of cellulose, hemicellulose, cellobiose, glucose, fructose and xylose into various high-value chemicals.

Anaerobic Digestion of Fruit and VegetableProcessing Wastes for Biogas Production

Abstract: The effect of feeding different fruit and vegetable wastes, mango, pineapple, tomato, jackfruit, banana and orange, was studied in a 60-liter digester by cycling each waste every fifth day in order to operate the digester as and when there was supply of feed. The characteristics of the anaerobically digested fluid and digester performance in terms of biogas production were determined at different loading rates (LR) and at different hydraulic retention times (HRT), and the maximum biogas yield of 06 rrd/kg VS added was achieved at a 20- day HR T and 40 kg TS m- 3day- 1 loading rate. The hourly gas production was observed in the digesters operated at 16 and 24 days HRT. The major yield (74"5%) of gas was produced within 12 h of feeding at a 16-day HRT whereas at a 24-day HRT only 59~93% of the total gas could be obtained at this time.

Innovations in applications and prospects of bioplastics and biopolymers: a review

Abstract: Non-biodegradable plastics are continually amassing landfills and oceans worldwide while creating severe environmental issues and hazards to animal and human health. Plastic pollution has resulted in the death of millions of seabirds and aquatic animals. The worldwide production of plastics in 2020 has increased by 36% since 2010. This has generated significant interest in bioplastics to supplement global plastic demands. Bioplastics have several advantages over conventional plastics in terms of biodegradability, low carbon footprint, energy efficiency, versatility, unique mechanical and thermal characteristics, and societal acceptance. Bioplastics have huge potential to replace petroleum-based plastics in a wide range of industries from automobiles to biomedical applications. Here we review bioplastic polymers such as polyhydroxyalkanoate, polylactic acid, poly-3-hydroxybutyrate, polyamide 11, and polyhydroxyurethanes; and cellulose-based, starch-based, protein-based and lipid-based biopolymers. We discuss economic benefits, market scenarios, chemistry and applications of bioplastic polymers.

Heterogeneous catalysts for hydrothermal liquefaction of lignocellulosic biomass: A review

Abstract: The biomass conversion into more valuable fuels represents one of the most viable routes for the exploitation of this material. Hydrothermal liquefaction is currently considered one of the most efficient processes to convert wet biomass into a bio-crude, which however requires expensive upgrading treatments to be used as biofuel. The use of catalysts able to directly improve bio-crude yield and quality during the reaction is of fundamental importance to increase the overall process efficiency. Homogeneous alkaline catalysts are the most studied, but they are not recoverable at the end of the process and so cannot be reused. The use of heterogeneous catalysts allows to overcome this issue making the recovery and reuse possible, maintaining anyway high activity and selectivity in the bio-crude production. The aim of this review is to critically summarize the effect of heterogenous catalyst addition on the hydrothermal liquefaction of lignocellulosic biomass, looking specifically at the improvement in bio-crude yield and quality. On the basis of literature data about the effect of heterogeneous catalyst addition on bio-crude yield and quality in the hydrothermal liquefaction of lignocellulosic biomass, a common catalytic action was identified allowing to group the several catalysts into four classes (alkaline metal oxides, transition metals, lanthanides oxides and zeolites). The hydrodeoxygenation activity of the catalysts, their effect on bio-crude yield and quality and the operating conditions used are highlighted. The highest bio-crude yields are reported using transition metals and lanthanide oxides which are able to guarantee, at the same time, a high-quality bio-crude.