Browsing by Author "Kumar, Gopalakrishnan"

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    A critical review on limitations and enhancement strategies associated with biohydrogen production
    (Elsevier Ltd, 2021-02-15T00:00:00) Banu J, Rajesh; Usman T M, Mohamed; S, Kavitha; Kannah R, Yukesh; K N, Yogalakshmi; P, Sivashanmugam; Bhatnagar, Amit; Kumar, Gopalakrishnan
    The potential to operate energy efficient and less expensive production methods are important in biohydrogen production. Biological hydrogen production is often constrained by less productivity. However, to obtain industrial level implementation, greater productivity is essential. Researches on various bioreactors configurations and influencing factors were deeply investigated in this regard. The bioreactors operated in batch mode are appropriate for preliminary optimization whereas industrial level execution needs continuous mode. The main objective of this review is to recap the limitations and constraints associated with bioreactor operation and to list out the enhancement approaches that are currently investigated for improved biohydrogen generation. Recent approaches designed towards biohydrogen production enhancement such as substrate pre-treatments, inhibitors removal, bioaugmentation, immobilization, effluent recycling, buffering capacity maintenance, exploitation of by-products etc., are reviewed thoroughly. � 2021 Hydrogen Energy Publications LLC
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    Lignocellulosic biomass-based pyrolysis: A comprehensive review
    (Elsevier Ltd, 2021-08-06T00:00:00) K N, Yogalakshmi; T, Poornima Devi; P, Sivashanmugam; S, Kavitha; R, Yukesh Kannah; Varjani, Sunita; AdishKumar, S.; Kumar, Gopalakrishnan; J, Rajesh Banu
    The efficacious application of lignocellulosic biomass for the new valuable chemicals generation curbs the excessive dependency on fossil fuels. Among the various techniques available, pyrolysis has garnered much attention for conversion of lignocellulosic biomass (encompasses cellulose, hemicellulose and lignin components) into product of solid, liquid and gases by thermal decomposition in an efficient manner. Pyrolysis conversion mechanism can be outlined as formation of char, depolymerisation, fragmentation and other secondary reactions. This paper gives a deep insight about the pyrolytic behavior of the lignocellulosic components accompanied by its by-products. Also several parameters such as reaction environment, temperature, residence time and heating rate which has a great impact on the pyrolysis process are also elucidated in a detailed manner. In addition the environmental and economical facet of lignocellulosic biomass pyrolysis for commercialization at industrial scale is critically analyzed. This article also illustrates the prevailing challenges and inhibition in implementing lignocellulosic biomass based pyrolysis with possible solution. � 2021
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    Statistical optimization of operating parameters of microbial electrolysis cell treating dairy industry wastewater using quadratic model to enhance energy generation
    (Elsevier Ltd, 2022-04-28T00:00:00) Rani, Gini; Banu, J. Rajesh; Kumar, Gopalakrishnan; Yogalakshmi, K.N.
    The performance of Microbial electrolysis cell (MEC) is affected by several operating conditions. Therefore, in the present study, an optimization study was done to determine the working efficiency of MEC in terms of COD (chemical oxygen demand) removal, hydrogen and current generation. Optimization was carried out using a quadratic mathematical model of response surface methodology (RSM). Thirteen sets of experimental runs were performed to optimize the applied voltage and hydraulic retention time (HRT) of single chambered batch fed MEC operated with dairy industry wastewater. The operating conditions (i.e) an applied voltage of 0.8 V and HRT of 2 days that showed a maximum COD removal response was chosen for further studies. The MEC operated at optimized condition (HRT- 2 days and applied voltage- 0.8 V) showed a COD removal efficiency of 95 � 2%, hydrogen generation of 32 � 5 mL/L/d, Power density of 152 mW/cm2 and current generation of 19 mA. The results of the study implied that RSM, with its high degree of accuracy can be a reliable tool for optimizing the process of wastewater treatment. Also, dairy industry wastewater can be considered to be a potential source to generate hydrogen and energy through MEC at short HRT. � 2022 Hydrogen Energy Publications LLC