Basudeb Saha

Excessive water production in ultradeep, extreme high-temperature and high-salinity (HTHS) carbonate reservoirs has emerged as a major challenge, reducing hydrocarbon productivity and creating substantial environmental and economic burdens. Herein, we report, for the first time, the synthesis of a novel, highly resilient, sustainable, self-healing, thermoresponsive chitin-based nanocomposite hydrogel for water shutoff, specifically tailored to endure extreme harsh conditions of 160 °C and 350,000 ppm salinity. The nanocomposite was synthesized via a near-zero-waste approach utilizing chitin and CaCO3 nanoparticles derived from shrimp shell biomass, employing a recyclable, CO2-switchable natural deep eutectic solvent (NADES)-assisted enzymatic process. The extracted chitin was copolymerized with vinyl ester sulfonated lignin (VESL), a green macromonomer derived from industrial lignin waste, and 1-vinylimidazole (VIm) via free radical polymerization. The hydrogel composition has been optimized using response surface methodology (RSM) with central composite design. The nanocomposite was thoroughly characterized by FTIR, 1H NMR, SEM, EDX, TGA, and DTG analysis. The optimized nanocomposite demonstrated a superior swelling ratio and viscoelastic properties even at an ultralow polymer concentration of 0.08 wt % across temperatures of 25 to 160 °C and salinities up to 350,000 ppm. Core-flooding experiments indicated effective fracture plugging with high RRF values of 300.5 ± 5.7 and 191.1 ± 4.8 (with plugging efficiencies of 99.7 ± 0.4% and 99.5 ± 0.5%, respectively) using ultralow nanocomposite concentrations of 0.08 wt % and 0.1 wt %, respectively. This research presents a sustainable strategy that integrates the CO2-switchable green extraction of chitin with lignin for valorization of marine and industrial biowaste into a high-performance self-healing hydrogel for water shutoff in ultra-HTHS reservoirs.

Liquid organic hydrogen carriers (LOHCs) offer a safe and scalable solution for hydrogen storage and transportation, overcoming many of the limitations of conventional compressed and liquefied hydrogen systems. Among the available LOHCs, the dibenzyltoluene/perhydro-dibenzyltoluene (DBT/18H-DBT) pair is particularly attractive due to its high theoretical hydrogen storage capacity (6.2 wt.%) and favourable handling characteristics. This study investigates the hydrogenation of DBT over a cost-effective 13 wt.% Ni/Al₂O₃ catalyst using a multiphysics modelling approach developed in COMSOL Multiphysics. A zero-dimensional (0D) kinetic model, assessed against available experimental data, was employed to investigate the effects of temperature and hydrogen pressure on conversion, intermediate formation, and selectivity, and was subsequently extended to a two-dimensional (2D) predictive modelling framework to evaluate reactor behaviour under continuous-flow conditions. The simulations identified an optimum operating window of 505–515 K and 2 MPa, achieving complete DBT conversion and 95–97% selectivity towards the fully hydrogenated product, 18H-DBT, while higher pressures provided only marginal additional benefits. The 2D reactor model further predicted a final 18H-DBT selectivity of 96.8%, confirming the suitability of these conditions for continuous hydrogenation. The developed modelling framework provides valuable insight into reactor-scale performance and offers a robust tool for the design and optimisation of efficient, economically viable LOHC hydrogenation systems based on nickel catalysts.

This paper presents a comprehensive design, implementation, and feasibility analysis of a sustainable styrene production plant that integrates conventional ethylbenzene dehydrogenation with bio-based feedstock processing. Located on the Gujarat coastline, India, the proposed facility is designed to produce 220,000 tonnes per year of styrene while addressing environmental, social, and economic sustainability objectives. Agricultural corn stover sourced from local farms is valorised via pretreatment, enzymatic hydrolysis, and two-phase simultaneous saccharification and fermentation (TPSSF), achieving ethanol yields of up to 477 kg per tonne of biomass. Bioethanol is subsequently alkylated with benzene over a beta-zeolite catalyst, delivering a 95% conversion with respect to bioethanol and 85.8% selectivity to ethylbenzene. This intermediate is then dehydrogenated at 550 °C using a potassium-promoted iron oxide catalyst to produce styrene with a 96.2% selectivity. Extensive heat integration, benzene recycling, and a steam-to-ethylbenzene ratio of 7:1 enhance energy efficiency and process robustness. Techno-economic analysis demonstrates that the plant remains commercially viable and profitable despite the incorporation of renewable feedstocks. The utilisation of corn stover reduces biomass waste and greenhouse gas emissions, lowers dependence on fossil resources, and supports local employment and supply chains. By embedding sustainability, safety, process integration, and economic assessment within a unified design framework, this work provides an industry-relevant and transferable model for low-carbon styrene manufacture aligned with UN Sustainable Development Goals 7, 12 and 13.

This innovative study explores bamboo pyrolysis for biochar production, critically evaluating methods and emphasising advanced separation techniques for syngas, including both condensable (bio-oil) and non-condensable gases.

A heterogeneous polybenzimidazole-supported Mo(VI) catalyst and tert-butyl hydroperoxide (TBHP) as an oxidising reagent have been utilised to establish a more environmentally friendly and greener alkene epoxidation process. A polybenzimidazole-supported Mo(VI) complex (PBI.Mo) has been prepared, characterised and evaluated successfully. The stability and catalytic activity of the produced catalyst have been evaluated for the epoxidation of 1,7-octadiene and 1,5-hexadiene in a jacketed stirred batch reactor to assess its performance towards these alkenes. The suitability and efficiency of the catalyst have been compared by studying the effect of reaction temperature, feed mole ratio of alkene to TBHP, catalyst loading, and reaction time on the yield of 1,2-epoxy-5-hexene and 1,2-epoxy-7-octene. Response surface methodology (RSM) using Box–Behnken Design (BBD) has been employed to design experimental runs and study the catalytic performance of the PBI.Mo catalyst for all batch experimental results. A quadratic regression model has been developed representing an empirical relationship between reaction variables and response, which is the yield of epoxides. The numerical optimisation technique concluded that the maximum yield that can be reached is 66.22% for 1,7-octadiene and 64.2% for 1,5-hexadiene. The reactivity of alkenes was observed to follow the sequence 1,5-hexadiene > 1,7-octadiene. The findings of this study confirm that the optimal reaction conditions vary between the two reactions, indicating differences in catalytic performance for each alkene.

As the world aims to address the UN Sustainable Development Goals (SDGs), it is becoming more urgent for heavy transportation sectors, such as shipping and aviation, to decarbonise in an economically feasible way. This review paper investigates the potential fuels of the future and their capability to mitigate the carbon footprint when other technologies fail to do so. This review looks at the technologies available today, including, primarily, transesterification, hydrocracking, and selective deoxygenation. It also investigates the potential of fish waste from the salmon industry as a fuel blend stock. From this, various kinetic models are investigated to find a suitable base for simulating the production and economics of biodiesel (i.e., fatty acid alkyl esters) and renewable diesel production from fish waste. Whilst most waste-oil-derived biofuels are traditionally produced using transesterification, hydrotreating looks to be a promising method to produce drop-in biofuels, which can be blended with conventional petroleum fuels without any volume percentage limitation. Using hydrotreatment, it is possible to produce renewable diesel in a few steps, and the final liquid product mixture includes paraffins, i.e., linear, branched, and cyclo-alkanes, with fuel properties in compliance with international fuel standards. There is a wide range of theoretical models based on the hydrodeoxygenation of fatty acids as well as a clear economic analysis that a model could be based on.

Fine chemicals are produced in small annual volume batch processes (often USD 10/kg). As a result of their usage in the production of speciality chemicals, in areas including agrochemicals, fragrances, and pharmaceuticals, the need for them will remain high for the foreseeable future. This review article assesses current methods used to produce fine chemicals with heterogeneous catalysts, including both well-established and newer experimental methods. A wide range of methods, utilising microporous and mesoporous catalysts, has been explored, including their preparation and modification before use in industry. Their potential drawbacks and benefits have been analysed, with their feasibility compared to newer, recently emerging catalysts. The field of heterogeneous catalysis for fine chemical production is a dynamic and ever-changing area of research. This deeper insight into catalytic behaviour and material properties will produce more efficient, selective, and sustainable processes in the fine chemical industry. The findings from this article will provide an excellent foundation for further exploration and a critical review in the field of fine chemical production using micro- and mesoporous heterogeneous catalysts.

In this study, a greener and more efficient alkene epoxidation process has been developed using a heterogeneous polybenzimidazole supported Mo(vi) catalyst and tert-butyl hydroperoxide (TBHP) as an oxidising reagent.

Fine chemicals are produced in small annual volume batch processes (often $10/kg). As a result of their usage in the production of speciality chemicals, in areas including agrochemicals, fragrances and pharmaceuticals, their necessity will remain high for the foreseeable future. This review article assesses current methods used to produce fine chemicals with heterogeneous catalysts, including both well-established methods as well as newer experimental methods. A wide range of methods utilising microporous and mesoporous catalysts has been explored, including their preparation and modification before use in industry. Their potential drawbacks, as well as benefits, have been analysed, with their feasibility compared to newer, recently emerging catalysts. The field of heterogeneous catalysis for fine chemical production is a dynamic and ever-changing area of research. This deeper insight into catalytic behaviour and material properties will produce more efficient, selective, and sustainable processes in the fine chemical industry. The findings from this article will provide an excellent foundation for further exploration and a critical review in this field of fine chemical production using micro- and mesoporous heterogeneous catalysts.