Department of Chemistry

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

CO2 Research and Green Technologies Centre

Agriculture forms the major part of our Indian economy. In the current world, agriculture and irrigation are the essential and foremost sectors. It is a mandatory need to apply information and communication technology in our agricultural industries to aid agriculturalists and farmers to improve vice all stages of crop cultivation and post-harvest. It helps to enhance the country’s G.D.P. Agriculture needs to be assisted by modern automation to produce the maximum yield. The recent development in technology has a significant impact on agriculture. The evolutions of Machine Learning (ML) and the Internet of Things (IoT) have supported researchers to implement this automation in agriculture to support farmers. ML allows farmers to improve yield make use of effective land utilisation, the fruitfulness of the soil, level of water, mineral insufficiencies control pest, trim development and horticulture. Application of remote sensors like temperature, humidity, soil moisture, water level sensors and pH value will provide an idea to on active farming, which will show accuracy as well as practical agriculture to deal with challenges in the field. This advancement could empower agricultural management systems to handle farm data in an orchestrated manner and increase the agribusiness by formulating effective strategies. This paper highlights contribute to an overview of the modern technologies deployed to agriculture and suggests an outline of the current and potential applications, and discusses the challenges and possible solutions and implementations. Besides, it elucidates the problems, specific potential solutions, and future directions for the agriculture sector using Machine Learning and the Internet of things.

School of Computer Science and Engineering

Vellore Campus

Ubiquitous Computing

Internet of Things and Machine Learning Applications for Smart Precision Agriculture

The present study aimed to assess the possibility of integrating natural attenuation (NA) and chemical oxidation (O) with the bio-electrocatalytic remediation (BET) process to remediate petroleum hydrocarbons contaminated soil. Six different reactors were operated, wherein in the first reactor was a NA system, and the second condition to the NA was supplemented with a chemical oxidant (NAO). These systems were compared with BET systems which were differentiated based on the position and distance between the electrodes. The study was performed by considering NA as a common condition in all the six different reactors viz., NA, NAO, NA + BET with 0.5 cm space amid electrodes (BETH-0.5), NAO + BET with 0.5 cm space amid electrodes (BETOH-0.5), NAO + BET with 1.0 cm space amid electrodes (BETOH-1.0), and NAO + BET with vertical electrodes at 1.0 cm distance (BETOV-1.0). The highest total petroleum hydrocarbons (TPH) degradation efficiency was observed with BETOH-0.5 (67 ± 0.8%) followed by BETOH-1.0 (62 ± 0.6%), BETH-0.5 (60%), BETOV-1.0 (56 ± 0.5%), NAO (46.6%), and NA (27.7%). In NA, the indigenous microorganisms remediate the organic contaminants. In the NAO system, KMnO4 actively breakdown the carbon-carbon double bond functional group. Further, in BETOH-0.5, an anodophilic bacteria enriched around the electrode reported enhanced treatment efficiency along with a maximum of 260 mV (1.65 mA). BET systems integrated with chemical oxidation processes were much more effective in the TPH removal process than an individual process. The BET method adopted here thus provides a good opportunity for bio-electrocatalytic remediation of TPH and resource recovery in the form of bioelectricity. © 2021 Elsevier Ltd

World University root node

Chemosphere

Bio-electrocatalytic remediation of hydrocarbons contaminated soil with integrated natural attenuation and chemical oxidant

Synergism during the co-pyrolysis of microalgae (CC), municipal solid waste (MSW), and their blends (CC/MSW) (w/w %), 25/75 (CM-1), 50/50 (CM-2), and 75/25 (CM-3), was evaluated based on thermal decomposition pattern, evolved gases, rate and extent of thermal decomposition, and kinetic parameters. Three stages of devolatilization attributed to dehydration, devolatilization of major structural compounds of biomass and decomposition of solid residues were noticed during the co-pyrolysis of biomass samples. The main pyrolysis stages for CC, MSW, CM-1, CM-2 and CM-3 were 175–520, 151-523, 164-504,168-510, 160–501 °C, respectively. Microalgae, CC, appeared to be thermally resistant, while MSW is noticed to be thermally sensitive. The kinetics analysis was studied by deconvoluting the DTG profile into independent stages, followed by application of isoconversional methods to evaluate the activation energy and the pre-exponential factor. Furthermore, the reaction mechanism of each stage was determined by using the master plot method. The semi-quantitative method was used to evaluate the evolved gases and CO, CO2 and H2 were noticed to be the dominant gas species. The obtained thermal and kinetic data for co-pyrolysis of microalgae and MSW can serve are basis for scale-up and reactor design of pyrolysis process for similar kind of waste streams. © 2020

Journal of the Energy Institute

Co-pyrolysis of microalgae and municipal solid waste: A thermogravimetric study to discern synergy during co-pyrolysis process

Water scarcity is perceived as a global systemic risk since there is an inexorable rise in water demand. An ecological engineering system mimics a natural ecosystem by balancing the trophic conditions for effective treatment of wastewater in a sequential manner. The present study was designed using emergent, floating and submerged macrophytic plants in a systematic approach. The study was evaluated with several components such as plants (water hyacinth, water lettuce and water thymes), aeration (supply of oxygen), and physical adsorption (activated carbon). Domestic wastewater collected from the local effluent treatment plant was treated individually and by combining all the components. Diverse experimental setups viz., lake sediment (control reactor), aeration, activated carbon blocks, water hyacinth, water lettuce, and water thymes were individually studied. Further the above components were combined, such as lake sediment + aeration + activated carbon blocks with plants like water hyacinth, water lettuce, and water thymes. The study inferred along with phytoremediation, and the external factors enhanced the treatment performances. Water hyacinth documented enhanced chemical oxygen demand removal efficiency of 85.71%, followed by water lettuce (80%), and water thymes (77.14%) along with the plants, both aeration, and activated carbon had stimulated the wastewater treatment. The highest removal efficiency of nitrate (70.23%), phosphate (63.64%), and sulphate (61.16%) were observed in water hyacinth due to its thick roots, and fibrous tissues reported effective treatment. The study hypothesized that these processes could be an effective strategy to restore the lakes and regulate the environmental flow. The study infers that an ecological engineering system symbiotically enables to self-organize the ecosystem within the boundary. © 2021 Elsevier Ltd

Journal of Environmental Management

Sustainable ecological engineering systems for the treatment of domestic wastewater using emerging, floating and submerged macrophytes

Desalination processes consume large amount of electricity and heat derived from fossil fuels to produce fresh water. In recent years, solar desalination emerged as a favorable method for sustainable fresh water production with less environmental impacts. A solar photovoltaic thermal collector is a combined system of solar photovoltaic and solar thermal collector that simultaneously generates electricity and thermal energy. The present work reviews photovoltaic thermal collector integrating desalination technologies such as solar still, humidification dehumidification, multiple effect distillation, reverse osmosis, multiple stage flash and membrane distillation. The primary focus is made on successful utilization of electricity and heat from the photovoltaic thermal collector in desalination systems to reduce cost, primary energy consumption and to improve overall system performance. Future opportunities and novel methods to improve/explore the photovoltaic thermal driven desalination systems are reported. Possibilities of photovoltaic thermal collector as energy source for other desalination technologies (electrodialysis, forward osmosis, vapor compression, adsorption desalination and etc.) are also presented. Comparative analysis shows that overall performance of photovoltaic thermal coupled desalination systems is better than desalination systems coupled with separate photovoltaic panel and/or solar thermal collector to meet the energy needs. The additional electricity generated from photovoltaic thermal desalination paves way for standalone desalination in remote location even though the initial costs are a tad higher. © 2021 Elsevier Ltd

Renewable and Sustainable Energy Reviews

A review on solar photovoltaic thermal integrated desalination technologies

Biomass is a renewable source and potentially sustainable fossil fuel replacement due to its availability, lower processing cost, high conversion, and lower life cycle carbon emissions. Pyrolysis can be used to convert biomass into bio-oil, but the quality of bio-oil is usually poor exhibiting high viscosity, thermal instability, and corrosiveness. This review article is focused on the application of catalytic pyrolysis towards obtaining high-quality bio-oil and advanced techniques for bio-oil characterisation. Structural arrangement (i.e., mesoporous, microporous), number of acid sites (Lewis and Brønsted acid sites), and amount of metal loading play a key role on deoxygenation reactions and selective production of aromatic hydrocarbons. Hierarchical zeolites doped with noble metals favour hydrogenation of C▬O or C〓O and reduce coke deposition in the production of polycyclic aromatics. Overall reaction mechanisms, aromatic yield and selectivity, the effect of Si/Al ratio, and process challenges of metal loaded zeolites are summarized. The advantages and disadvantages of different types of advanced analytical techniques for bio-oil characterisation are also discussed. The results showed that two-dimensional gas chromatography (2D GC) technique can identify 70% of chromatograph from bio-oil analysis. However, there is need to combine analytical techniques to accurately quantify bio-oil components. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.

Biomass Conversion and Biorefinery

A review on catalytic pyrolysis for high-quality bio-oil production from biomass

The present work involves an investigation of Spirulina platensis bio-oil (SPO) with its engine performance in the compression-ignition engine. Spirulina platensis biomass was successfully cultivated in standard Zarrouke medium for few decades, hence in this work S. platensis is cultivated in Zarrouke and economic Zarrouke media show the maximum growth rate of 0.30 and 0.29 g/L/d respectively. The calculated average activation energy (Ea) values are 100.76, 157.21, 153.88, 167.67, 291.38, and 186.60 kJ/mol for Kissinger, Kissinger-Akahira-Sunose, Tang, Flynn-Wall-Ozawa, Friedman, and Coast Redfern (Jander 3D diffusion) models respectively. Friedman model shows highest Ea (365.81 kJ/mo1 at 0.7) value with more accuracy than others, hence this model is most favored for S. platensis biomass pyrolysis process. Positive G and H values imply that the pyrolysis process follows spontaneity with endothermic nature. A single-stage fixed bed reactor is utilized to extract SPO with 20% yield at 600 °C and its characterized by physico-chemical, spectral (GC-MS & FTIR), elemental, heat of vaporization, Reid vapor pressure, dynamic viscosity and surface tension methods. Engine performance and emission analysis were performed 5% and 10% SPO blends with 0.50:4.75:4.75 and 1:4.50:4.50 (SPO: Ethanol: Diesel) ratio, respectively under 25%, 50%, 75% and 100% load conditions. 5% SPO blend shows better brake thermal efficiency with lower brake specific fuel consumption values than 10% blend. Furthermore, the emissions of HCs, (NO)x and smoke are slightly higher in SPO blends than diesel. © 2021 Elsevier Ltd.

Journal of Environmental Chemical Engineering

A comprehensive investigation on Spirulina platensis - Part I: Cultivation of biomass, thermo-kinetic modelling, physico-chemical, combustion and emission analyses of bio-oil blends in compression ignition engine

Pyrolysis of tomato peel waste in an indigenous Auger reactor is reported. Tomato peel was subjected to elemental analysis and physicochemical characterisation. The higher heating value of the tomato peel was estimated to be 22.50 MJ kg−1. Thermogravimetric analysis of tomato peel was performed to estimate the temperature of pyrolysis process. Thermal cracking of tomato peel was carried out at different temperatures ranging from 450 °C to 650 °C. The bio oil yield was found to 14%, 17.5%, 32%, 40% and 36% at 450 °C, 500 °C, 550 °C, 600 °C and 650 °C respectively. Kinetic modelling of the tomato peel pyrolysis was performed with three different model free methods to evaluate the activation energy. The activation energy of tomato peel pyrolysis at different heating rates, 5 °C min−1, 10 °C min−1, 15 °C min−1, 20 °C min−1 and 25 °C min−1 were reported to be 112.7 kJ mol−1, 113.85 kJ mol−1 and 234.47 kJ mol−1 respectively by Kissinger, Kissinger Akahira Sunose and Ozawa Flynn Wall models. Tomato peel oil was subjected to Gas chromatography - Mass spectroscopy and Fourier transform infrared spectroscopy analysis to determine the compounds and functional groups. The kinematic viscosity of the tomato peel oil was found to be 11.82 cSt. The flash point of the tomato peel oil was estimated to be 94 °C. Different blends of tomato peel oil and diesel were subjected to testing in a 4-stroke water cooled open chamber diesel engine to evaluate the performance and emission characteristics analysis. The Brake thermal efficiency of 5% blend of tomato peel oil was estimated to be 31.5% under full load condition. Carbon Monoxide emissions of tomato peel oil blends were found to be lesser in comparison with diesel fuel. Techno-economic analysis of the tomato peel pyrolysis was also reported. © 2020 Elsevier Ltd

VIT Unitversity

Journal of Cleaner Production

Experimental investigation and kinetics of tomato peel pyrolysis: Performance, combustion and emission characteristics of bio-oil blends in diesel engine

Waste heat rejection to ambient from air conditioning systems is one of the major causes of urban heat island effect. Increased urbanization and living standards leads to increased water demand. In this work, a new design of vapor compression refrigeration system integrated with humidification-dehumidification desalination is proposed without changing the actual size of vapor compression refrigeration system. The present system consists of a compressor, an evaporative condenser, an expansion device, an evaporator and a suction fan. Water to be desalinated is sprayed over the evaporative condenser. The evaporative condenser and the evaporator are also acting as humidifier and dehumidifier of humidification-dehumidification desalination. In order to recover waste heat rejected to ambient, cooling of evaporative condenser using indoor air and subsequent condensation of hot humid air in evaporator is proposed in this work. The proposed system performance such as desalination yield, cooling output, coefficient of performance, gained output ratio, energy utilization factor are analysed for various ambient temperature and relative humidity. The maximum desalination yield and cooling output are 7.35 LPH and 1.89 kW respectively. The highest system coefficient of performance, gained output ratio and energy utilization factor are 2.16, 6.11 and 8.27 respectively at ambient temperature of 20 °C and 30% RH. The annual average desalination and cooling output are 25.884 m3/year and 4.26 MWh/year respectively. The exergy efficiency of the proposed system is 39.34%. The unit cost of desalination is estimated to be $0.0096/L. © 2020

Performance analysis of a novel augmented desalination and cooling system using modified vapor compression refrigeration integrated with humidification-dehumidification desalination

Sustainable resources management, incorporating energy markets and resources such as electricity, fossil fuels, renewable and sustainable energy capital is essential for society to understand production and conversion of various forms of energy, their current as well as future supply. Waste-to-energy (WTE) or energy-from-waste (EFW) is a well-identified transitional technology which could prevent complete depletion of renewable resources. In our present study, the selected microalgae (Chlorella pyrenoidosa) was cultured in paddy-soaked wastewater (PWW) using outdoor raceway ponds of 50 L capacity where biotransformation of nutrients (NH3–N removal: 75.89 ± 0.69%; PO4–P removal: 73.71 ± 0.75%; yield co-efficient YN: 6.12 mg biomass/mg of N; YP: 7.77 mg biomass/mg P) has occurred with better growth and biochemical composition (dry biomass weight: 1.56 ± 0.11 g/L; chlorophyll: 15.57 ± 0.14 mg/L; specific growth rate (SGR): 0.42/d; lipids: 27.47 ± 1.41% biomass; carbohydrates: 23.77 ± 1.00% and protein: 46.12 ± 3.55%). Further, the obtained algal lipid was identified for a wide range of fatty acid methyl esters (FAME) and consequently brought forward to in-situ single-step transesterification by optimizing reaction conditions. Central composite design (CCD) of response surface methodology (RSM) has given optimized conditions of sample amount: 2 g (wet); methanol sulphuric acid volume: 3 mL; and hexane volume: 4 mL, under the reaction temperature of 90 °C for maximum biodiesel conversion (46.54% of algal lipids). The outcome of our current research may add value to the application and development of WTE technology for sustainable energy conservation. © 2020 Elsevier Ltd

Department of Environmental and Water Resources Engineering

School of Civil Engineering

Biomass and Bioenergy

Outdoor cultivation of Chlorella pyrenoidosa in paddy-soaked wastewater and a feasibility study on biodiesel production from wet algal biomass through in-situ transesterification