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Biopesticides offer a sustainable and efficient alternative to synthetic pesticides, providing a safer and more eco-friendly solution to pest management. The present work proposes an innovative approach that integrates crop protection and wastewater treatment using thermophilic microalgal strain Chlorella thermophila (CT) cultivated in nutrient-rich dairy wastewater as a growth medium. The microalgae was cultivated mixotrophically and was able to reduce both organic carbon as well as nutrient load of the dairy wastewater efficiently. The integrated circular biorefinery approach combines biomass cultivation, extraction of biopesticide compounds, and conversion to biocrude. The antimicrobial activity of the biopesticidal extracts against Xanthomonas oryzae and Pantoea agglomerans, the causative agent of bacterial rice blight, is assessed through in vitro studies. The biomass extract obtained is able to inhibit the growth of both the above-mentioned plant pathogens successfully. Mass spectroscopy analysis indicates the presence of Neophytadiene that has previously been reported for the inhibition of several pathogenic bacteria and fungi. Several other value-added products such as linoleic acid and nervonic acids were also been detected in the microalgal biomass which have extremely high nutraceutical and medicinal values. Furthermore, the study investigates the potential for co-production of biocrude from the biorefinery process via hydrothermal liquefaction. Overall, the findings of this present work represent an innovative and sustainable approach that combines wastewater treatment and crop protection using microalgal biomass. [ABSTRACT FROM AUTHOR]

[Display omitted] • Factors influencing the membrane based dewatering phenomenon are addressed critically. • This review covers the use of Patterned and Fenton membranes to mitigate fouling. • Membrane utilization in microalgal biorefinery applications is examined. • Potential of HTL-AP valorization using membrane technology is proposed. • Perspectives and future prospects of downstream processing are pointed out. The future potential of microalgae as a sustainable feedstock for biofuels and other value-added products remain uncertain. While microalgae demonstrate higher environmental advantages and productivity compared to many other feedstocks, the production costs and downstream processing pose significant challenges that impede the adoption of this technology. This review discusses the primary strategies employed by the research community for microalgae harvesting, focusing on the innovative advancements made to enhance filtration performance and mitigate fouling issues. In addition, this contribution provides an overview of the benefits associated with membrane technologies in effectively extracting high-value compounds from microalgal cells, such as lipids, proteins, and carbohydrates. The review also highlights the significance of membrane-based processes in recovering nutrients, biofuel precursors, and other valuable compounds from hydrothermal liquefaction (HTL) aqueous phase, contributing to the overall sustainability and circular bioeconomy goals of biomass conversion processes. [ABSTRACT FROM AUTHOR]

In this work the effects of nutrient availability and light conditions on CO 2 utilization and lipid production in Micractinium pusillum KMC8 is reported. The study investigated the ideal nitrogen concentrations for growth and nitrogen utilization in a 15% CO 2 environment. Logistic and Gompertz models were employed to analyze the kinetics of KMC8 cell growth. Compared to 17.6 mmol L−1 control nitrogen, which generated 1.6 g L−1 growth, doubling and quadrupling nitrogen concentrations boosted biomass growth by 12.5% and 28.78%. At 8.6 mmol L−1 nitrogen, the growth decreased but lipid productivity increased to 18.62 mg L−1 day−1. At 70.6 mmol L−1 nitrogen, elevated nitrogen levels maintained an alkaline pH above 7 and enhanced CO 2 mitigation, achieving 2.27% CO 2 utilization efficiency. Nitrogen shows a positive correlation with higher rates of carbon and nitrogen fixation. The investigation extends to find out the influence of phosphorus and light conditions on microalgae. Increasing light intensity incrementally from 150 to 1200 μmol m−2 s−1 with more phosphorus increased biomass productivity by 85% (255 mg L-1 day−1) and lipid productivity by 2.5-fold (84.76 mg L-1 day−1), with 3.3% CO 2 utilization efficiency compared to directly using 1200 μmol m−2 s−1. This study suggests a water recycling-fed batch cycle with gradual light feeding, which results in high CO 2 fixation (1.1 g L−1 day−1), 7% CO 2 utilization, and significant biomass and lipid productivity (577.23 and 150 mg L−1 day−1). This approach promotes lipid synthesis, maintains carbon fixation, and minimizes biomass loss, thus supporting sustainable bioenergy development in a circular bio-economy framework. [Display omitted] • Investigation of the synergistic effects of nitrogen, phosphorus, and light on microalgae. • Enhanced carbon capture efficiency by combined outputs of biomass and lipids. • The nitrogen and light availability modulate the excretion of organic carbon. • Phosphorus and light crucial for CO 2 fixation and lipid production in nitrogen limitation. • High-density fed-batch maximizes CO 2 utilization, lipid production, and water recycling. [ABSTRACT FROM AUTHOR]

A simple and easy green synthesis of silver nanoparticles (Ag NPs) was prepared using Sapindus emarginatus stem bark extract and anchored over graphitic carbon nitride (g-C3N4) surface. The synthesized materials characterized by UV–Visible, XRD, FESEM, FETEM, FT-IR and Raman spectroscopy ensured the development of Ag NPs anchored over the g-C3N4 surface. The prepared catalyst was utilized for Methylene Blue (MB) dye degradation through visible light photocatalysis. The optimization of operational parameters, like the effect of catalyst dosage, H2O2 concentration and slurry pH, was performed. The results exhibited that compared to pristine g-C3N4, photocatalytic efficacy was enhanced two-fold in Ag@g-C3N4. Also, the prepared Ag@g-C3N4 showed a faster catalytic MB dye reduction (25 s) in the presence of NaBH4. The catalyst was recovered from the reaction solution by centrifugation and reused for five consecutive cycles. The results showed that there was no significant loss in the efficiency of the catalyst. These results confirmed that the green synthesized Ag@g-C3N4 is likely advantageous for organic pollutants degradation. [ABSTRACT FROM AUTHOR]

This study evaluates the pyrolysis kinetics and resource recovery potential from mixtures of bamboo sawdust (BS) biomass, and a COVID-19 waste material, body coverall (BC). The pyrolysis kinetics of BS, BC and their binary mixtures was modeled using distributed activation energy modeling approach. BS pyrolysis was described using three pseudocomponents, viz., cellulose, hemicellulose and lignin, and BC using two pseudocomponents, polypropylene and an additive. For pyrolysis of individual BS and BC, the activation energy was highest for lignin (272.1 kJ mol−1) and the additive (321.7 kJ mol−1) pseudocomponent. The activation energy (240.7 kJ mol−1) and change in enthalpy (234.9 kJ mol−1) were found to be the lowest for lignin for the blend BS:BC (3:1 wt/wt). Analytical pyrolysis revealed alkenes (63.3%) and oxygen containing aromatics (57.4%) as the major compounds from BC and BS, respectively. Cyclic alcohols were the major compounds from pyrolysis of BS–BC mixtures. This study demonstrates that blending BC with BS lowers the energy barrier for pyrolysis to generate valuable chemicals. [Display omitted] [ABSTRACT FROM AUTHOR]

Conversion of wastes to energy and other value-added products is considered as a suitable method towards energy security. Wastes from various sources are becoming potential feedstocks for energy production through different techniques. The economy and sustainability of these processes demand the use of low-cost catalysts. Red mud (RM) is one of the most abundantly produced industrial wastes from aluminum industries. Such a huge production of RM, its alkaline nature and the presence of a small quantity of radioactive elements make it an environmental liability. Out of various utilization methods, RM as a catalyst for different chemical processes has been very successful. Presence of many valuable metals in RM, in particular, Fe makes it a suitable catalyst for energy production through processes such as pyrolysis, hydrotreating, transesterification and H 2 production from biomass and other sources. This article critically reviews the advances in sustainable energy production through different processes mentioned above by RM based catalysts. Different characterization, activation and stability study of RM along with outcomes and mechanism of these processes are discussed. Furthermore, drawbacks associated with the low catalytic activity of RM and works that need to be carried out in the future for the improvement of its catalytic activity are discussed in detail. Image 101037 • Recent development in catalytic utilization of red mud for energy synthesis were explored. • Physical and chemical properties of RM were briefly explained. • Pyrolysis, hydrodeoxygenation, H 2 production and transesterification were discussed. • Catalytic activity and reaction pathways of energy synthesis were proposed. • Perspective to enhance the activity of RM for energy production were proposed. [ABSTRACT FROM AUTHOR]

In the present study, the effect of biomass bed thickness and distance between successive beds on pyrolytic products yield were carried out. Sawdust of pine wood and sal wood, as well as husk of areca nut, were used as a biomass feedstock. To achieve maximum liquid yield, 500 °C temperature, 80 °C min−1 heating rate, 0.5 mm particle size and 100 mL min−1 gas flow rate was selected as optimum conditions. An equal amount of biomass was placed in six different bed arrangements while dividing the amount of biomass equally among the number of beds as well as keeping an equal distance between the successive beds. Further, the entire reactor was fitted inside the furnace so as to distribute the heat uniformly throughout the rector which also signified that each biomass bed has the same thermal profile at any time. It was found that liquid properties were better (lower viscosity, higher heating value) at fourth bed arrangement than in other bed arrangements. FTIR and GC-MS analysis confirmed the presence of aromatic, phenol, ester, ether, alcohol, acid, and amide groups. Gas chromatography also confirmed that with increasing temperature, the amount of hydrogen and hydrocarbons increased significantly while the formation of CO 2 was reduced. Image 1 • Effect of bed height and thickness on biomass pyrolytic products yields were studied. • Temperature, heating rate and particle size were optimized. • Optimization of bed arrangements resulted in higher and better liquid. • Complete characterization of pyrolytic oil was carried out. • Amounts of H 2 , HCs increased with increase in temperature whereas CO 2 reduced. [ABSTRACT FROM AUTHOR]

Abstract The combined effect of anions of ionic liquids (IL) and anti-solvents on pre-treatment and dissolution mechanisms of biomass are not well studied. To reveal the above effect, three different ionic liquids composed with fixed cation ([EMIM]+) but varied anions were studied for Miscanthus dissolution. Results showed that [EMIM]+[Ac]– was very good in altering the cellulose structure and crystallinity followed by enzymatic digestibility with a sugar yield of 0.98 (g/g of cellulose). The IL [EMIM]+[HSO 4 ]– was very efficient to remove lignin and partially solubilize hemicellulose, however, the sugar yield was low (0.43 g/g of cellulose) compared with [EMIM]+[MeSO 3 ]– and even the untreated Miscanthus. The regenerated biomass with water-acetone mixture (1:1 v/v) as anti-solvent resulted in higher glucose yield. The hydrogen bond basicity (β value) correlated well with cellulose crystallinity, lignin removal, and glucose yield. Graphical abstract Image 1 Highlights • [EMIM]+[Ac]– drastically decreased the cellulose crystallinity of Miscanthus. • [EMIM]+[HSO 4 ]– solubilized almost entire amount of lignin present in Miscanthus. • Enzymatic digestibility is very high for [EMIM]+[Ac]– pretreated biomass. • Glucose yield increased with water-acetone mixture (1:1 v/v) as anti-solvent. • β value related well with crystallinity index, lignin removal and glucose yield. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Monoraphidium sp. KMC4 found to be novel strain among eight other DSW isolates. • Biochemical, CHNS, TGA, FTIR validated KMC4′s potential as bioenergy feedstock. • FAME with 78% of C16/C18 confirmed the feasibility of biodiesel production. • LEMB characterization also suggested it as a high-value bioenergy feedstock. • Optimal biomass to energy conversion validated zero-waste biorefinery approach. Abstract The present study investigated the feasibility of domestic sewage wastewater (DSW) as an alternate to fresh-water microalgae growth media towards high-value bioenergy feedstock production. Eight native microalgal strains were screened from DSW and the effect of raw DSW (RDSW), and autoclaved DSW (ADSW) on growth and bioremediation potential were evaluated and compared with control BG11 medium. The study confirmed RDSW as a potential growth medium while Monoraphidium sp. KMC4 showed superior biomass (1.47 ± 0.08 g L−1) and lipid yield (436.01 ± 0.06 mg L−1). The corresponding values for bioremediation of ammonia, nitrate, phosphate, as well as COD remained within 88–100%. CHNS, biochemical, TGA, FTIR, FAME analysis of KMC4 confirmed it's potential as bioenergy feedstock. Additionally, a comprehensive characterization of lipid-extracted microalgae biomass (LEMB) was carried out which suggested that LEMB can be used as a growth promoter as well as feedstock for biogas, bioethanol, and bio-oil production. [ABSTRACT FROM AUTHOR]

In this study, two different unexploited indoor plants, Epipremnum aureum and Dracaena braunii were used to produce clean and sustainable bio-electricity in a plant microbial fuel cell (PMFC). Acid modified carbon fiber brush electrodes as well as bare electrodes were used in both the PMFCs. A bentonite based clay membrane was successfully integrated in the PMFCs. Maximum performance of E. aureum was 620 mV which was 188 mV higher potential than D. braunii . The bio-electricity generation using modified electrode was 154 mV higher than the bare carbon fiber, probably due to the effective bacterial attachment to the carbon fiber owing to hydrogen bonding. Maximum power output of 15.38 mW/m 2 was obtained by E. aureum with an internal resistance of 200 Ω. Higher biomass yield was also obtained in case of E. aureum during 60 days of experiment, which may correlate with the higher bio-electricity generation than D. braunii. [ABSTRACT FROM AUTHOR]

Highlights • Non-edible seed Neem was converted to fuels and chemicals. • Catalytic pyrolysis enhanced the yield and fuel properties of pyrolytic liquid. • Formation CO 2 decreased with increase in temperature. • Energy content of non-condensable gas increased with increase in temperature. • GC–MS & FTIR analysis of liquid confirmed presence of various valuable chemicals. Abstract In this work, a non-edible seed Neem (Azadirachta indica) was used to find out it’s potential to produce fuels and chemicals using thermo-catalytic pyrolysis. The physiochemical characterization confirmed the seed’s bioenergy potential. Thermal and catalytic pyrolysis were carried out at optimum conditions (500 °C temperature, 80 °C min−1 heating rate, 0.5 mm particle size and 80 mL min−1 nitrogen gas flow rate) which produced maximum liquid yield (49.53 wt. % at thermal, 54.06 wt. % and 52.08 wt. % for K 2 CO 3 and Zeolite respectively at Biomass/Catalyst ratio 8:1). The comparative study of thermal and catalytic pyrolytic liquid confirmed that the yield as well as fuel properties of pyrolytic liquid were enhanced with the use of catalysts. It was also noticed that the energy content of gases increased with increasing pyrolysis temperature. Further, with increase in pyrolysis temperature, the amounts of hydrogen and hydrocarbons increased significantly, but at the same time, the formation of carbon dioxide was reduced. [ABSTRACT FROM AUTHOR]

[Display omitted] • Lignin extraction from bamboo was optimized by ultrasound-assisted organosolv process. • Temperature was the most significant parameter affecting the lignin yield. • Maximum lignin yield of 65.81 ± 2.40% was obtained under sono-assisted pretreatment. • High purity lignin of 95.37 ± 1.17% was obtained from this pretreatment. For a sustainable biorefinery, reduction in the recalcitrance of lignocellulosic biomass is very crucial for the efficient utilization of each fraction. The present work investigated an integrated pretreatment method to recover high-quality lignin along with the cellulose-rich pulp. An optimization study employing response surface methodology investigated the synergistic effects of ultrasound and organosolv pretreatment from Bambusa tulda (bamboo). The optimal condition (180 °C, 55 min, and 30 min sonication) resulted in 65.81 ± 2.40% of lignin yield with 95.37 ± 1.17% purity. A reduction in 7.85% yield and 1.54% purity of lignin with organosolv pretreatment highlighted the efficacy of sonication in lignin extraction. Ultrasound resulted in homolytic cleavage of the lignin-carbohydrate bond that enhanced delignification and increase the cellulose crystallinity. NMR, FTIR, GPC, and TGA of lignin suggested the superiority of sonication in maintaining lignin quality. A significant amount of β-O-4 linkages in extracted lignin is favorable for its subsequent valorization. [ABSTRACT FROM AUTHOR]

Areca nut husk is the most promising alternative source of low-cost raw materials because it contains a considerable amount of five-carbon monosaccharide sugar in the form of xylose. This polymeric sugar can be isolated and transformed into a value-added chemical using fermentation. To extract sugars from areca nut husk fibers, preliminary pretreatment, such as dilute acid hydrolysis (H2SO4), was performed. The hemicellulosic hydrolysate of areca nut husk can produce xylitol through fermentation, but toxic components inhibit the growth of microorganisms. To overcome this, a series of detoxification treatments, including pH adjustment, activated charcoal, and ion exchange resin, were carried out to reduce the concentration of inhibitors in the hydrolysate. This study reports a remarkable 99% removal of inhibitors in the hemicellulosic hydrolysate. Subsequently, a fermentation process using Candida tropicalis (MTCC6192) was executed with the detoxified hemicellulosic hydrolysate of areca nut husk, yielding an optimum xylitol yield of 0.66 g/g. This study concludes that detoxification techniques like pH adjustment, activated charcoal, and ion exchange resins are the most economical and effective methods for eliminating toxic compounds in hemicellulosic hydrolysates. Therefore, the medium derived after detoxification from areca nut hydrolysate may be considered to have significant potential for xylitol production. [ABSTRACT FROM AUTHOR]

The present study reports pyrolysis behavior of three waste biomass using thermogravimetric analysis to determine kinetic parameters at five different heating rates. Physiochemical characterization confirmed that these biomass have the potential for fuel and energy production. Pyrolysis experiments were carried out at five different heating rates (5–25 °C min −1 ). Five model-free methods such as Kissinger-Akahira-Sunose (KAS), Ozawa-Flynn-Wall (OFW), Friedman, Coats-Redfern, and distributed activation energy (DAEM) were used to calculate the kinetic parameters. The activation energy was found to be 171.66 kJ mol −1 , 148.44 kJ mol −1 , and 171.24 kJ mol −1 from KAS model; 179.29 kJ mol −1 , 156.58 kJ mol −1 , and 179.47 kJ mol −1 from OFW model; 168.58 kJ mol −1 , 181.53 kJ mol −1 , and 184.61 kJ mol −1 from Friedman model; and 206.62 kJ mol −1 , 171.63 kJ mol −1 , and 160.45 kJ mol −1 from DAEM model for PW, SW, AN biomass respectively. The calculated kinetic parameters are in good agreement with other reported biomass. [ABSTRACT FROM AUTHOR]

[Display omitted] • Microalgae as a potential candidate for the production of value-added bioproducts. • Mixotrophic mode improved nutrient removal efficiency and biomass productivity. • Integration of crop protection and wastewater treatment in a biorefinery approach. • An efficient approach for the treatment of BLB disease in rice cultivation has been developed. The present work aims on developing an eco-friendly strategy that couples the remediation of dairy wastewater with crop protection strategy using microalgal biomass for sustainable agriculture. In the present study, the microalgal strain Monoraphidium sp. KMC4 was cultivated in dairy wastewater. It was observed that the microalgal strain is able to tolerate up to as high as 2000 mg/L of COD and utilize the organic carbon and other nutrient component of the wastewater for biomass production. The biomass extract demonstrates excellent antimicrobial activity against the two phytopathogens (Xanthomonas oryzae and Pantoea agglomerans). GC–MS analysis of the microalgae extract revealed phytochemicals such as chloroacetic acid and 2, 4- di tert butylphenol that are responsible for the inhibition of the microbial growth. These preliminary results indicates that integration of microalgal cultivation and nutrient recycling from wastewaters for the production of biopesticides is a promising prospect for the replacement of synthetic pesticides. [ABSTRACT FROM AUTHOR]

A variety of low-cost hybrid clay based ceramic membranes were developed for application in plant based microbial fuel cells (PMFCs). The membranes were prepared by using locally available clay mixed with varying concentrations of sodium carbonate, sodium metasilicate, boric acid, bentonite, and fly ash. Physiochemical characterization was carried out by using TGA, XRD, FESEM, FTIR, flexural strength test, water uptake, proton conductivity, oxygen and acetate diffusion and compared with Nafion117. Performance of ceramic membranes in PMFCs was evaluated by using the plant E. aureum with carbon fiber brush electrode. Membrane having composition of clay-55%, bentonite-15%, flyash-15%, Na 2 Co 3 -8%, Na 2 Sio 3 -2%, H 3 Bo 3 -5% exhibited maximum power density of 22.38 mW m−2 which was 78% higher than control (100% clay) with a decrease in internal resistance from 346 Ω to 234 Ω. The study demonstrates that the addition of bentonite, fly ash, Na 2 Co 3 , Na 2 Sio 3 and H 3 Bo 3 with clay at a concentration of 15%, 15%, 8%, 2%, and 5% respectively improved membrane cation transport ability, reducing oxygen diffusion and substrate crossover at the same time. The membrane demonstrated extreme stability for long term operations involving more than six months' period. The low cost of production of clay based ceramic membrane at ₹1279/ft2 can be a good alternative to highly priced commercially available proton exchange membranes. [Display omitted] • Hybrid ceramic membranes made using clay, bentonite, fly ash, Na 2 Co 3 , Na 2 Sio 3 and H 3 Bo 3 for application in PMFC. • Four times more proton transfer in novel ceramic membrane as compared to clay membrane. • 78% higher power density than the clay membrane with decrease in internal resistance from 346 to 234 Ω. • Hybrid ceramic membranes were more stable for long term usage. • The cost of making is extremely low (₹1279/ft2) as compared to nafion117 (₹80,580/ft2). [ABSTRACT FROM AUTHOR]

In this study, a low-cost, sustainable biosorbent parthenium (P. hysterophorus L.) weed powder was investigated for the treatment of Pb contaminated wastewater. Physicochemical characteristics of the biosorbent were measured, namely, bulk density as 0.42 g cm-3, porosity as 45%, BET surface area as 20.79 m2 g-1, particle size as <125 μm, moisture content as 68% and point of zero charge as 5.6. The various parameters of biosorption process were examined. The maximum percentage removal of Pb ion achieved was 98.3% with 1.0 g L-1 of biosorbent dose for 50 mg L-1 initial Pb ion concentration at process condition of pH 4, temperature 30 °C (303 K), agitation speed 200 rpm and 150 min of equilibrium contact time. The equilibrium data were examined by various rate kinetics models and adsorption isotherm models. Sorption of Pb ion onto biosorbent was confirmed by Fourier transform infrared spectroscopy (FTIR) transmittance spectra and field-emission scanning electron microscopy and energy-dispersive X-ray (FESEM-EDX) analysis of native as well as Pb ion adsorbed biosorbent. The change in thermodynamic parameters, such as Gibbs free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) was calculated. The results suggest that biosorption process using parthenium (P. hysterophorus L.) weed powder as biosorbent was a spontaneous, feasible and efficient method for treatment of Pb-bearing wastewater. [ABSTRACT FROM AUTHOR]

The current work reports the ab initio calculations on Ionic Liquids (ILs) with bituminous and anthracite coal particles using both Density Functional Theory (DFT) and solvation predictions using COnductor like Screening MOdel for Real Solvents (COSMO-RS) model. The commercial cations used in the study were 1-butyl-1-methylpyrrolidinium ([BMPYR]), 1-methyl-3-propylimmidazolium ([MPIM]), Tributylmethylammonium ([TMA]) and Tributylmethylphosphonium ([MTBP]). The corresponding anions were methyl carbonate ([CH 3 CO 3 ]), dicyanamide ([N(CN) 2 ]), bis(trifluromethylesulfonyle)imide ([Tf 2 N]) and methylsulfate ([MeSO 4 ]). A three-tier approach comprising of HOMO-LUMO energies, quantum descriptors (electronegativity, electrophilicity, global hardness, global softness); and Infinite Dilution Activity Coefficient (IDAC) by COSMO-RS model were chosen for studying the simultaneous interaction. 1-butyl-1-methylpyrrolidinium methylcarbonate [BMPYR][CH 3 CO 3 ] and 1-methyl-3-propylimmidazolium methylcarbonate [MPIM][CH 3 CO 3 ] were the recommended IL's on the basis of HOMO-LUMO band energy gap. A similar trend for IL-coal interactions were followed up and confirmed by the quantum descriptors and IDAC predictions. A direct correspondence between reported swelling ration and excess Gibb's energy has also been attempted. [ABSTRACT FROM AUTHOR]

In this work, Al metal ions were doped on natural hydroxyapatite by wet chemical impregnation route. The hydroxyapatite was obtained from waste cooked fish bones after proper treatment. The developed catalyst was characterized. From BET analysis it was found that the surface area and pore volume has increased up to 157.96 m 2 g −1 and 0.8062 mL g −1 after Al doping followed by calcination. The FE-SEM micrographs showed the homogenous porous structure distribution on the surface of the Al doped catalyst. From TGA analysis, it was found that the catalyst was stable up to 1000 °C. A comparison of the developed catalyst with other catalysts reported in literature confirmed the superiority of this catalyst. Doping of Al ion and calcination played a significant role during transesterification of neem ( Azadirachta indica ) oil which was clearly envisaged. The kinetics of transesterification was thoroughly studied at optimal condition, which was found out using response surface methodology. The physical properties of the transesterified product were calculated by following the usual ASTM protocols. The catalyst reusability was also studied. [ABSTRACT FROM AUTHOR]

In this work, pyrolysis technology was used to convert biomass and waste to energy. Polystyrene wastes (Thermocol) were co-pyrolyzed with non-edible seed (such as Karanja and Niger) to enhance the quality of pyrolytic oil. The aim was to enhance the calorific value, cold flow properties and to reduce the viscosity of co-pyrolytic oil. For that purpose, waste polystyrene was mixed with the seeds in different proportions. The yield and quality of co-pyrolytic oil was compared with the thermal pyrolytic oil of these seeds as reported in literature. This study confirmed that co-pyrolysis of waste polystyrene and seed not only enhanced the conversion of seed to product but also significantly affected the co-pyrolytic oil fuel properties. Viscosity of the co-pyrolytic oil was reduced with increasing the ratio of seed to waste polystyrene. Similarly, higher calorific value co-pyrolytic oil was obtained at 2:1 ratio compared to other ratios. The comparison between the seed thermal pyrolytic oil and co-pyrolytic oil confirmed that co-pyrolysis of waste polystyrene and biomass altered the composition of pyrolytic oil which had a positive influence on the quality of co-pyrolytic oil. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel three-chamber modular design plant microbial fuel cell was constructed. • All the components of the PMFC can be easily changed, making operation easy. • A composite ceramic membrane was used for the first time in PMFC research. • Long-term self-sustainability of PMFCs system was established. • Improved power density and current density of 24.56 mW m−2 and 52 mA m−2, respectively were obtained. In this work, a novel three-chamber modular plant microbial fuel cell (PMFC) was designed and tested for long term sustainable generation of bioelecricity. The modular setup makes operation easy and hassle-free as placing every components, i.e., membranes, electrodes, and even changing the plants, becomes very convenient. The novel membrane assembly design combined with pre-activated electrodes with increased surface area helped promote biofilm growth and electrocatalytic activity on anode and cathode surface. The new design resulted in improved performance and stability of the PMFC system for long term usage with minimal maintenance. The use of composite membrane consisting of clay, bentonite, and fly ash mixture was used for the first time in PMFC research and proved to be an excellent alternative to existing expensive Nafion membranes. The power density and current density has increased up to 24.56 mW m−2 and 52 mA m−2 respectively, which is 63% increase in power production and is amongst the highest in PMFC research. [ABSTRACT FROM AUTHOR]

This work aims to identify an appropriate food-grade multi-component draw solute composition with enhanced permeate flux and reduced reverse solute flux. This study also highlights the role of the membrane in an efficient FO process. The osmotic properties of selected mixed-salt solutions of magnesium chloride, sodium chloride, sodium sulphate, and potassium chloride were investigated. Based on osmotic pressure, three multi-solute draw solute (DS) compositions were selected for preparation of concentrated tea extract using forward osmosis process. The role of membrane in the efficient membrane process was evaluated by comparing two commercially available hollow fibre forward osmosis membrane. Compared to salts with monovalent ions (such as NaCI and KCD, the SSF of the divalent ions salts (such as MgCl2 and Na2SO4) is reduced by 57.42% due to their larger hydrated radius. The optimised multi-component draw solute performance was compared with single-salt draw solute by maintaining almost the same osmotic pressure. The results of the lab-scale experimental studies revealed that compared to single salt DS Uw = 17.66 L m-2 h-1 and specific salt flux, SSF = 1.53 g L-1) the identified multi-component DS provides an enhanced permeate flux (16.91 L m-2 h-1) with significantly reduced SSF (0.86 g L-1). [ABSTRACT FROM AUTHOR]

Highlights: [•] Pyrolysis of Niger seed was investigated with and without the presence of catalyst. [•] The yield of oil during thermal and catalytic pyrolysis was more or less similar. [•] Kaolin at 8:1 ratio was more suitable to enhance calorific value of pyrolytic oil. [•] CaO at 8:1 ratio was able to reduce the viscosity of pyrolytic oil. [•] Pyrolytic oil contains both saturated and unsaturated hydrocarbon compounds. [ABSTRACT FROM AUTHOR]

Abstract: This work reports the kinetic study of the pyrolysis of four non-edible oil seeds such as Mahua, Karanja, Niger and Linseed conducted at a heating rate of 5, 10 and 15 °C min−1 under nitrogen atmosphere. The relation between kinetic parameters and degradation rate was observed with respect to temperature and heating rate. The results indicated that the kinetic parameters were very close to each other and directly proportional to temperature and heating rate. The comparison of kinetic parameters related to heating rate concluded that heating rate had a direct affinity towards activation energy and pre-exponential factor. The TG-DTG analysis indicated three stages of thermal degradation during pyrolysis of the oil seeds whereas DSC analysis point towards the endothermic and exothermic pathway of pyrolysis. The presence of hemicelluloses, cellulose and lignin was determined on the basis of degradation temperature and their respective functional groups in the seeds observed by FTIR analysis. [Copyright &y& Elsevier]

Highlights: [•] Thermal and catalytic pyrolysis of one non-edible oil seed Mahua was carried out. [•] 525°C was the optimum temperature to produce maximum pyrolytic liquid. [•] Yield of pyrolytic oil was higher for catalytic pyrolysis than thermal pyrolysis. [•] CaO as catalyst increased the calorific value and decreased the viscosity. [•] The catalytic pyrolytic oil has closer fuel properties with that of diesel. [ABSTRACT FROM AUTHOR]

Highlights: [•] 55.17%, Weight basis yield was reported for thermal pyrolysis of Karanja seed. [•] CaO, Al2O3 and Kaolin were used as catalysts for catalytic pyrolysis. [•] The yield of pyrolytic oil was high at 8:1 feed to catalyst ratio. [•] Al2O3 and Kaolin proved to be better than CaO in terms of pyrolytic liquid yield. [•] All the catalysts were capable to enhance the fuel quality of pyrolytic oil. [ABSTRACT FROM AUTHOR]

Highlights: [•] A Cr(VI) reducing strain Bacillus cereus was isolated from Cr(VI) contaminated soil. [•] Complete reduction of Cr(VI) for concentrations of 10–50mgL−1 was obtained. [•] Bioreduction potential of cell free extracts of Bacillus cereus was evaluated. [•] NADPH and NADH were found to be best suitable electron donors. [•] Effect of electron metabolic inhibitors on bioreduction of Cr(VI) was reported. [ABSTRACT FROM AUTHOR]

In this work, the bioreduction of Cr(VI) by immobilized cells of Halomonas sp was reported. Ca alginate, acryl amide and agar were tested as the matrices for immobilization. Ca alginate was found to be the suitable matrix among the different matrices studied. Of the various dosages of inoculum studied 2 g/L was found to be the optimum. Glucose at 1 g L-1 was completely utilized by the immobilized Halomonas sp even in the presence of Cr(VI) at 40 mg L-1. The optimum pH for the bioreduction of Cr(VI) by immobilized Halomonas sp was found to be pH 6. The mechanical strength of the beads plays an essential role in the bioreduction process. Halomonas sp entrapped in a alginate matrix reported a maximum of 98.9 % of reduction for an initial Cr(VI) concentration of 10 mg L-1. The alginate beads can be reused for 3 times with slight drop in the percentage reduction. The presence of other metals decreased the bioreduction percentage. [ABSTRACT FROM AUTHOR]

Abstract: In this work the bioreduction of Cr(VI) from aqueous solutions by Halomonas sp. was reported. Medium pH had significant effect on the bioreduction of Cr(VI). Glucose at 1000mgL−1 was essential for growth of Halomonas sp. as well as bioreduction of Cr(VI). A maximum specific Cr(VI) reduction rate of 0.74mgg−1 h−1 was obtained for an initial Cr(VI) concentration of 40mgL−1. A maximum of 98.6% reduction of Cr(VI) was reported for an initial concentration of 10mgL−1. Other initial Cr(VI) concentrations studied viz. 20, 30 and 40mgL−1 resulted in 96.3%, 94.4% and 93.3% of Cr(VI) reduction respectively. pH 7 was found to be optimum for the bioreduction of Cr(VI) with free cells of Halomonas sp. Cell free extracts reported a maximum reduction efficiency of 89.65% for an initial metal concentration of 40mgL−1. The optimum pH for CFE on Cr(VI) reduction was 6.5. NADPH and NADH were found to be the best electron donors. EDTA, NaN3, KCN, PCP inhibited the reduction of Cr(VI) by cell free extract. [Copyright &y& Elsevier]

Areca nut husk is an agricultural bio-waste with massive potential for producing value-added chemicals by conversion of xylose present in it through fermentation. This study aimed to optimise the production of xylitol from areca nut husk hemicellulosic acid hydrolysate (as the substrate) by using Candida tropicalis (MTCC 6192). Response Surface Methodology (RSM) and Artificial Neural Network (ANN) were compared for fermentation process optimisation in modelling and prediction. Agitation, pH, temperature, xylose concentration and operation time were considered variable parameters. The maximum concentration of xylitol obtained was around 9.96 g/L under designed conditions. Crystallisation analysis was conducted to separate pure xylitol crystal from fermented broth, followed by characterisation of xylitol crystal such as X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Thermogravimetric Analysis (TGA), Differential scanning calorimetry (DSC) and Raman analysis. DSC analysis revealed that the melting process of commercial xylitol crystals after crystallisation (CXCAC) was observed at 93.71 °C with enthalpies of 210.7 J/g. However, almost similar results were observed for xylitol crystals from fermentation broth (XCFB), with a melting point at 91.73 °C and enthalpies of 220 J/g. [Display omitted] • Fermentation Process Optimisation Based on ANN and RSM technique and their comparison for xylitol production. • Crystallisation of xylitol from fermented broth (purity around 85%), followed by characterisation. • Characterisation and comparison of xylitol crystal obtained after fermentation (Crystallinity index 76.85%), with commercial xylitol (Crystallinity index 81.44%). [ABSTRACT FROM AUTHOR]

Abstract: In the present work the potential of Parthenium (P. hysterophorus L.) weed to remove Cr(VI) ions from aqueous solution was reported. FTIR was used to study the functional groups present on the surface of the biosorbent and it was found that carboxyl, amine and alkane groups were the leading Cr binding groups. Effect of various parameters such as contact time, temperature, pH, agitation speed, biosorbent dose and initial Cr(VI) concentration on the biosorption was investigated by batch process. The equilibrium data was well described by both Langmuir and Freundlich isotherms. The biosorption capacity of Parthenium weed for Cr(VI) was found to be 24.5mgg−1 at pH 1.0, 0.1g biomass dose, 200rpm, 160min equilibrium time and 20°C. The study of thermodynamic parameters confirmed that the biosorption of Cr(VI) onto Parthenium weed was feasible, spontaneous and exothermic within 20–60°C. The magnitude of heat of biosorption was calculated as 7.83kJmol−1 which confirmed that biosorption followed the physical process. Kinetic evaluation of experimental data showed that biosorption of Cr(VI) closely followed pseudo-second-order kinetics and surface diffusion was found to be the rate controlling step. [Copyright &y& Elsevier]

Abstract: In this work the potential of Catla catla scales to remove Cr(VI) ions from aqueous solutions was investigated as a function of time, initial Cr(VI) concentration, initial pH, biomass dose and agitation speed. Optimum biosorption conditions were found to be pH 1.0, 0.05gL−1 biomass dosage, 200rpm agitation speed and 180min equilibrium time. The fitness of biosorption equilibrium data for Freundlich, Langmuir and Dubinin–Radushkevich isotherm models were tested. It was found that Freundlich model was better suitable for biosorption of Cr(VI) ions onto C. catla biomass. Three kinetic models viz. the Lagergren first-order and pseudo-second-order and intra-particle diffusion model were used to analyze the biosorption data and the results suggested that the pseudo-second-order model represented the best correlation. FTIR spectrum analysis revealed that O–H, N–H and C–O groups were the leading Cr(VI) binding groups. [Copyright &y& Elsevier]

Abstract: This paper examines the use of multi-stage or cascade ultrafiltration systems for continuous fractionation of model proteins human serum albumin (HSA) and human immunoglobulin G (HIgG). A three-stage, countercurrent ultrafiltration system was able to generate continuous HSA and HIgG streams with high purity and recovery. Pulsed sample injection ultrafiltration experiments showed that selectivity could be significantly affected by protein–protein interactions. The molar ratio of proteins in the feed was affected by the sieving coefficients of the proteins, particularly that of the preferentially transmitted one. Simulated results obtained with effective sieving coefficient data from pulsed sample injection ultrafiltration which factored in protein–protein interactions were found to be in good agreement with experimental results. The selectivity and hydraulic permeability as a function of time in a continuous fractionation process run under optimized conditions were determined to examine the feasibility of operation for extended duration. [Copyright &y& Elsevier]

Abstract: A mathematical model for predicting the hydrodynamic behavior of a multi-stage external loop airlift reactor operating in three stages has been developed. The present model is based on macroscopic balances of the gas–liquid separator, external downcomer and spatially averaged, 1D mass and momentum balances in the riser. Using only the physical properties of the gas and liquid phases, the reactor dimensions and the superficial gas velocity, the model predicts gas holdup profiles, gas and liquid velocity profiles, and pressure profiles in the riser for a two-phase bubbly flow. It has been observed that the values of gas holdup obtained are in the range of 44–52%. Empirical correlations are used to represent frictional and drag effects, but there are no adjustable parameters in the model. Results indicate that a pressure of 9.3×10−4 N/m2 were achieved at a dimensionless riser position of 1.0. The results predicted by the model are in excellent agreement with the experimental data reported in literature for a multi-stage external loop airlift reactor. [Copyright &y& Elsevier]

[Display omitted] • Valorization of de-oiled microalgal biomass as heterogeneous acid catalyst. • Hydrophobic carbon acts as potential support for sulfonated carbon catalysts. • The catalyst exhibited high catalytic activity and stability. • High FAME yield was obtained with improved fatty acid composition. • FAME yield >90% was obtained after four successive reuse cycles. In this study, a novel carbon-based solid acid catalyst was synthesized by carbonization of de-oiled microalgal biomass followed by sulfonation. The effect of catalyst synthesis conditions such as carbonization temperature, sulfonation time, and H 2 SO 4 concentration on the surface acidity of the catalyst and free fatty acid conversion was determined. The de-oiled microalgal biomass-based solid acid (DMB) catalyst was predominantly composed of carboxylic, phenolic, and sulfonic groups as indicated by the FTIR analysis and supported by the XPS analysis. The catalyst was further characterized by various methods to determine its physiochemical properties. A maximum fatty acid methyl ester (FAME) yield of 94.23% for microalgal oil (AO) and 96.25% for waste cooking oil (WCO) was obtained under optimized transesterification conditions. The catalyst exhibited high catalytic activity (FAME yield >90%) until the fourth cycle. Most of the biodiesel properties were within the permissible limit of EN 14,212 and ASTM D6751 standards. [ABSTRACT FROM AUTHOR]

Arachis hypogaea hulls, an agricultural waste, were used to prepare activated carbon by chemical activation with zinc chloride under four different activation atmospheres. The most important parameter in chemical activation was found to be the chemical ratio (activating agent/precursor). Carbonization temperature and time are the other two important variables, which had significant effect on the pore structure of carbon. The maximum Brunquer-Emmett-Teller (BET) surface area and micropore volume of the activated carbon was found to be 418 m2/g and 0.28 cm3/g, respectively. The activated carbon developed shows substantial capability to adsorb phenol from aqueous solutions. The kinetic data were fitted to the models of intraparticle diffusion, pseudo-second-order, and Lagergren, and followed more closely the pseudo-second-order chemisorption model. The isotherm equilibrium data were well fitted by the Langmuir and Freundlich models. Solution pH has significant effect on adsorption and the maximum uptake of phenol was reported at pH 3.5. [ABSTRACT FROM AUTHOR]

Abstract: In this work, a novel multi-stage external loop airlift reactor has been designed to remove phenol from wastewater by means of its adsorption onto the surface of activated carbons. The multi-staging has been achieved by hydrodynamically induced continuous bubble generation, breakup and regeneration. The continuous rupture and bursting of bubbles creates localized turbulence and recirculation, which helps in faster transfer of trace pollutants to the active sites of the solid adsorbents. Thus, the pollutants get adsorbed to the surface of the solid adsorbents due to continuous agitation. Different operating parameters that affect the performance of the reactor are the superficial gas velocity, liquid circulation velocity, concentration of the pollutant present in wastewater, contact time and the carbon loading. The results show that the removal time as well as the activated carbon loading for this system were quite lower as compared to simple batch adsorption systems. The kinetic data were fitted to the models of intra-particle diffusion, pseudo-second-order and Lagergren, and followed more closely the Lagergren pseudo-first-order model. Langmuir and Freundlich models were used to study the adsorption isotherms. A correlation has been developed to predict the efficiency of percentage removal of phenol and found to be highly significant from statistical point of view. [Copyright &y& Elsevier]

Abstract: This paper discusses the use of a novel tangential-flow, three-stage, countercurrent cascade ultrafiltration configuration for continuous purification of monoclonal antibody Campath-1H from simulated mammalian cell culture supernatant. The main limitation of conventional ultrafiltration based bioseparation, particularly when using a single-stage system is the trade-off between recovery and purity. The aim of this study was to try to improve both purity and recovery of the monoclonal antibody by using the novel cascade ultrafiltration system. Purification experiments were carried out with the three-stage cascade system as well as with single-stage and two-stage versions of the proposed system for comparison. The recovery and purification factor were both significantly higher with the three-stage system. The highest purity obtained using the three-stage cascade system was 85%. The experimental purity and recovery were compared with corresponding values obtained by simulation and found to be in reasonably good agreement. [Copyright &y& Elsevier]

Abstract: This paper reports on the experimental investigation carried out to evaluate the interfacial area, a, and liquid-side volumetric mass transfer coefficient, k L a, to characterize a multi-stage external loop airlift reactor (with contraction and expansion disks), which has been conceived, designed, and fabricated as an equipment to remove trace pollutants from wastewater. In addition, it has versatile use as a gas–liquid contactor in chemical process industries. In the experimental range of gas and liquid flows investigated, the maximum interfacial area and volumetric mass transfer coefficient obtained was in the order of 300m2/m3 and 0.05s−1, respectively. Correlations developed for predicting the interfacial area and liquid-side volumetric mass transfer coefficient have been found to be encouraging and highly significant from statistical analysis. [Copyright &y& Elsevier]

Abstract: In the present investigation a novel multi-stage external loop airlift reactor with hydro-dynamically induced continuous bubble generation, breakup and regeneration has been proposed. The system has been designed to operate with relatively large sized bubbles, so that interfacial circulation can be induced in the liquid–bubble interfaces and faster transfer of components can take place by turbulent diffusion through the interface of the bubbles and also due to the physical rupture and reformation of the bubbles. The system was also designed to operate in three stages operating in series so that in each stage completely deaerated liquid could be brought in contact with freshly generated bubbles. Detailed studies on the gas holdup and liquid circulation velocity have been carried out with respect to various values of superficial gas as well as liquid velocities. The gas holdup of the proposed multi-stage system is 45% higher than the single stage system, which results in better mass transfer characteristics. Empirical correlations describing the performance of the proposed reactor have been presented in this paper. [Copyright &y& Elsevier]

Abstract: This paper reports the research findings of a laboratory-based study on the removal of Cr(VI) from solution using the biomass (both roots and stems) of the non-living Eichhornia Crassipes as a biosorbent. The effect of physico-chemical parameters like pH, sorbent dose, contact time and initial concentrations were investigated. Although the Lagergren first order model was applicable to some of the data, the pseudo-second-order reaction model was applicable to all data. The Freundlich isotherm was found to represent the measured sorption data well. The Fourier transform infrared spectrometry showed that the hydroxyl group was the chromium-binding site within pH range (pH 1–5) where chromium does not precipitate. The results indicated that the biomass of E. Crassipes is suitable for development of efficient biosorbent for the removal of chromium from wastewater of chemical and allied process industries. [Copyright &y& Elsevier]

Abstract: Activated carbons prepared from Tectona grandis sawdust, a timber industry waste, have been examined for the removal of phenol from aqueous solutions. The activated carbon was prepared by zinc chloride activation under four different activation atmospheres, to develop carbons with well-developed porosity. Experiments were carried out at different chemical ratios (activating agent/precursor). Effects of carbonization temperature and time are the important variables, which had significant effect on the pore structure of carbon. Developed activated carbon was characterized by SEM analysis. Pore volume and surface area were estimated by Hg porosimetry and BET surface area analyses. The carbons showed surface area and micropore volumes of around 585m2/g and 0.442cm3/g, respectively. The activated carbon developed showed substantial capability to adsorb phenol from aqueous solutions. The kinetic data were fitted to the models of Lagergren, pseudo-second-order and intraparticle diffusion, and followed closely the pseudo-second-order chemisorption model. The Freundlich and Langmuir isotherm models were well fitted. The solution pH markedly affected the sorption process. The maximum uptake of phenol was found to be 2.82mg/g at pH 3.5. [Copyright &y& Elsevier]

Abstract: Different structured activated carbons were prepared from Terminalia arjuna nuts, an agricultural waste, by chemical activation with zinc chloride for the adsorption of Cr(VI) from dilute aqueous solutions. The most important parameter in chemical activation was found to be the chemical ratio (activating agent/precursor, g/g). Carbonization temperature and time are the other two important variables, which had significant effect on the pore structure of carbon. A high surface area of was obtained at a chemical ratio of 300%, carbonization time and temperature of 1h and 500°C, respectively. The activated carbon developed shows substantial capability to adsorb Cr(VI) from dilute aqueous solutions. The parameters studied include pH, adsorbent dosage, contact time, and initial concentrations. The kinetic data were best fitted to the Lagergren pseudo-first-order model. The isotherm equilibrium data were well fitted by the Langmuir and Freundlich models. The maximum removal of chromium was obtained at pH 1.0 (about 99% for adsorbent dose of 2g/l and 10mg/l initial concentration). [Copyright &y& Elsevier]

[Display omitted] • Red mud (RM) derived catalyst for the direct glucose conversion to 5-HMF. • Red mud composition provided the suitable Lewis acid sites. • Carbon coating followed by -SO 3 H grafting produced the Bronsted acid sites. • Low reaction time owing to the microwave-induced fast catalytic reaction. • Appreciable activity and stability of the RM-based catalyst. Though suitable for the fructose conversion to 5-hydroxymethylfurfural (5-HMF), sulfonated carbon catalysts are inefficient for the direct glucose transformation to 5-HMF due to the lack of appropriate Lewis acids. Here, we have reported an efficient and inexpensive catalyst by suitably modifying red mud (RM), a by-product from the aluminum industry. The AD-1:1/SO 3 H catalyst produced by the acid (HCl) treatment, carbon coating, and SO 3 H grafting on RM exhibited enhanced surface area, mesoporous characteristics, and suitable Lewis and Bronsted acid sites. The XRD, FTIR, and XPS analysis suggested Fe 2 (SO 4) 3 , Fe 2 O 3 , and various carbon functionalities as the major active components in the AD-1:1/SO 3 H catalyst. The NH 3 -TPD analysis revealed an appreciable acid site density of 6.8 mmol g−1. Under microwave heating at 180 °C, 30 min, and 90:10 DMSO/water weight percentage ratio, the catalyst produced a d -glucose conversion and 5-HMF yield of 93.05 % and 51.5 %, respectively. [ABSTRACT FROM AUTHOR]

• Manilkara zapota seed is a waste biological resource available in India. • This seed was pyrolyzed over ZSM-5 in a semi-batch reactor. • Yield of biochar decreased with increase in temperature from 400 to 600 °C. • Introduction of catalysts reduced oxygenated compounds and increased the hydrocarbons. • Catalyst also increased the energy content of pyrolytic oil. The present study addressed the thermal and catalytic pyrolysis of Manilkara zapota seeds (CK) using a semi-batch reactor to understand the effect of process parameters and ZSM-5 on the yield and properties of pyrolytic end products. The physicochemical results endorsed the inherent competence of CK for production of renewable fuels and allied chemicals. Pyrolysis was conducted at varying biomass to catalysts ratios (B/C) (3:1, 6:1, 8:1 and 10:1, respectively) at optimized process conditions. The pyrolysis results confirmed that thermal pyrolysis produced a higher yield of pyrolytic liquid (45.22 wt%) than catalytic pyrolysis (37.98 wt%) at 8:1 B/C ratio. However, the introduction of catalyst improved the properties of catalytic pyrolytic oil vis-à-vis thermal pyrolytic oil by dampening its oxygenated products and viscosity, while increasing the gross heating value (40.38 MJ kg−1). The FTIR study of thermal and catalytic pyrolytic oil confirmed the presence of water, acid, alkane, aromatic, and phenol while GC–MS results demonstrated the use of the catalyst at optimised conditions predominantly reduced the oxygenated products and acids while substantially increased the hydrocarbons. Furthermore, the characterisation of CK biochar confirmed its potential towards utilisation in various industrial and domestic applications. [ABSTRACT FROM AUTHOR]

• Renewable non-edible seeds were used for pyrolysis. • Seven models were used to determine kinetic parameters. • Kinetic reaction data showed good agreement with experimental data. • VZ and DAEM methods produce minimal error compared with others. The present study addressed the kinetics characteristics and pyrolysis behaviour of waste biomass Azadirachta indica (NM) and Phyllanthus emblica kernel (AM) in a thermogravimetric analyzer. Six model-free techniques such as Kissinger-Akahira-Sunose, Distributed Activation Energy Model, Friedman, Coats-Redfern, Ozawa-Flynn-Wall, Vyazovkin and Criado method were employed to evaluate the kinetic parameters at five varying heating rates (10–50 °C min−1). The physicochemical inspection directed that both the biomass had excellent prospects to produce energy and finest chemicals. FTIR study pointed strong evidence of moisture, protein, acid, and aromatics. The average apparent activation energy was found to be 176.66, 193.67, 196.06, 177.32 and 204.23 kJ mol−1 for NM and 184.77, 195.10, 189.95, 186.46, 184.57 kJ mol−1 for AM for KAS, OFW, FM, DAEM and VZ respectively. Further, master plot and thermodynamic study of AM and NM revealed that pyrolysis went through various reaction mechanisms at the time of pyrolysis. [ABSTRACT FROM AUTHOR]

Magnetically separable monometallic and bimetallic Au and Pt NPs anchored on TiO 2 nanocomposite were prepared using dahlia flower extract through a greener approach. The prepared nanoparticles (NPs) act as an efficient active metal-based catalyst for glycerol oxidation reaction (GOR) and organic compounds reduction reaction (ORR). The phytochemicals present in dahlia flower extract acts as reducing and stabilizing agent for the development of metal NPs on TiO 2 surface. For bimetallic (Fe 3 O 4 @TiO 2 –AuPt) NPs, the conversion efficiency for GOR was found to be 2-fold higher than those of monometallic NPs. The products of GOR over magnetically separable monometallic and bimetallic catalysts were analyzed by HPLC and products such as formic acid (FA), glycolic acid (GCA), glyceric acid (GLA), and tartronic acid (TA) were detected. In addition, ORR of 4-nitrophenol (4-NP), methylene blue (MB) and congo red (CR) in the existence of sodium borohydride (NaBH 4) were studied. It was found that the reduction reactions were completed within a few seconds for mono- and bimetallic nanocomposites. Comparatively, Fe 3 O 4 @TiO 2 –AuPt nanocomposite showed much higher efficacy (8, 6 and 5 s) for 4-NP, MB and CR reduction along with very good stable catalytic activity (∼98%) after six cycles. We hypothesize that the improved yield in GOR and faster reduction in ORR by Fe 3 O 4 @TiO 2 –AuPt nanocomposites are related to the synergistic effect of metal alloy formation and support materials. Image 1 • Magnetically separable Au@TiO 2 , Pt@TiO 2 , and Au–Pt@TiO 2 nanocomposite were synthesized. • Dahlia flower extract was used as reducing, capping and stabilizing agent for the green synthesis. • Bimetallic Au–Pt@TiO 2 showed boosting catalytic oxidation of glycerol to formic acid. • The prepared nanocomposites exhibited enhanced catalytic reduction of organic compounds. • Synergistic effect of bimetallic NPs with supporting materials was observed. [ABSTRACT FROM AUTHOR]

• Valorization of waste eggshells to produce a flocculating agent. • Impact of bioflocculant concentration, pH and temperature on zeta potential reported. • Experimental data well fitted to pseudo-second order model with R2 ˃ 0.99. • After harvesting, medium was recycled and supported the growth of microalgae. • FAME composition of lipid was not altered due to the use of this bioflocculant. Waste eggshell-derived bioflocculant was used for harvesting T. obliquus in a circular bioeconomy approach. It was found that 120 mg L−1 bioflocculant can flocculate 98.62 ± 0.43% of T. obliquus cells within 25 min at optimal pH 4.0 and temperature 35 °C. The influence of bioflocculant concentration, pH and temperature on zeta potential was evaluated to understand the flocculation mechanism. Microscopic and FESEM-EDX images were analyzed to evaluate the microalgal structural changes. Adsorption mechanism of bioflocculant over the microalgal cells was determined by performing adsorption kinetic studies. Pseudo-second order kinetic model was a suitable fit for the data obtained from the experiments, which indicated chemisorption as the probable mechanism. The spent medium recovered after harvesting process was successfully recycled for subsequent cultivation of T. obliquus , thus reducing the dependency on fresh medium. The FAME composition of the biomass treated with bioflocculant was not altered. [ABSTRACT FROM AUTHOR]

• Dahlia flower is an abundant and low-cost biological resource. • XRF analysis confirmed the presence of useful compounds. • Kinetic and thermodynamic parameters were calculated to understand its pyrolysis behavior. • Pyrolysis experiments were performed in Py-GC–MS at multiple temperatures. • Py-GC–MS analysis confirmed formation of higher amount of hydrocarbons at 550 °C. To explore the bioenergy potential, kinetic and pyrolysis behavior of waste dahlia flowers (DF), model-free methods and Py-GC–MS were used. Kinetic characteristics of DF biomass were estimated by adopting four model-free methods, Kissinger-Akahira-Sunose (KAS), Ozawa-Flynn-Wall (OFW), Friedman, and Distributed Activation Energy (DAEM). Further, functional groups, the presence of mineral matter in DF biomass, and mineral compounds present in the inorganic residue were analyzed using FTIR, EDX, and XRF. Physicochemical analysis results confirmed its bioenergy potential for conversion into renewable fuel and valuable chemicals. The kinetic results of DF biomass showed that activation energy varied with conversion value, and the thermodynamic analysis indicated multiple step pyrolysis. FTIR analysis confirmed the presence of hemicellulose, cellulose, and lignin in biomass. EDX and XRF analysis also revealed the presence of various useful mineral matter, which had a positive effect during pyrolysis. Py-GC–MS results confirmed that at a lower temperature (500 °C), the formation of ester, nitrogen containing compounds and acid were higher, while at higher temperatures (550 °C and 600 °C), the formation of oxygenated compounds were reduced and the production of hydrocarbons and alcohols increased. [ABSTRACT FROM AUTHOR]