Walnut (Julgans regia L.) shells, an agro-forestry waste, are a rich source of phytochemicals with anti-oxidative and medicinal properties. Whilst recent research efforts focus on waste valorization, the present investigation demonstrates a process to extract and characterize bio-components from physically pretreated walnut shells. Pretreatment was undertaken using microwave irradiation and ultra-sonication with two different solvents (methanol and acetone). The extract obtained was optimized using Response Surface Methodology (RSM). Further, the bio-components in the extract were identified using GCMS and FTIR analyses. Through the experimental runs, it was observed that pretreatment enhanced the total extract yield from the process relative to conventional Soxhlet extraction. As a method of pretreatment, microwave irradiation was found to suit the extraction better than ultra-sonication. In addition, acetone performed better as a solvent than methanol in the bio-components recovery. Relative to conventional Soxhlet extraction, microwave pretreatment allowed for enhanced separation by 4.06 folds for methanol and 5.25 for acetone. The yield was found to be the highest (46 mg/g) while using acetone, when pretreated with microwaves at 180 W for 4 min. © 2016, Technical University of Budapest. All rights reserved.

Mahesh Ganesapillai

Department of Chemical Engineering

School of Chemical Engineering

Vellore Campus

Mathew M

Singh A

Simha P.

Fulltext

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

Periodica Polytechnica Chemical Engineering

Resource-Efficient Technologies

Optimization studies on extraction of phytocomponents from betel leaves

Preliminary studies were performed to demonstrate a 'value from waste' concept for recovering polyphenols from waste Tamarindus indica L. by solvent extraction assisted by microwaves and/or ultrasound. To aid formulation of process guidelines, the influence of precursor size, microwave power, ultrasonication intensity and time were investigated. It was found that extract from tamarind shells contained (-)-epicatechin although the seed coat allowed for higher extraction. An optimum extract yield of 62.35 mg and 60.45 mg (per 100 g of dry solid) were obtained for microwave (180 W) and ultrasonication (intensity: 40%) pre-treatment of tamarind seeds of 0.2 mm size using ethanol. © 2017 Elsevier Ltd.

Materials Today: Proceedings

Preliminary isolation, recovery and characterization of polyphenols from waste Tamarindus indica L.

Microwave pretreatment is a promising and unsophisticated technique for energy recovery in solid waste management. The present investigation was focused on microwave activated carbonization of mixed solid waste (MSW). The effect of process parameters such as size of particles, temperature and duration of carbonization, microwave output power for pretreatment, irradiation time and amount of additives added during microwave heating were studied. The most important factors that influenced MW drying (pre-treatment) were found to be the sample mass and the Microwave output power. Microwave induced carbonization not only overcomes the disadvantages of conventional heating method such as low heat transfer rate but also improves the quality of final carbonization products. © 2017 Elsevier Ltd.

Preparation of Activated Carbon from Municipal Organic Solid Wastes

To highlight the shortcomings in conventional methods of extraction, this study investigates the efficacy of Microwave Assisted Extraction (MAE) toward bioactive compound recovery from pharmaceutically-significant medicinal plants, Adathoda vasica and Cymbopogon citratus. Initially, the microwave (MW) drying behavior of the plant leaves was investigated at different sample loadings, MW power and drying time. Kinetics was analyzed through empirical modeling of drying data against 10 conventional thin-layer drying equations that were further improvised through the incorporation of Arrhenius, exponential and linear-type expressions. 81 semi-empirical Midilli equations were derived and subjected to non-linear regression to arrive at the characteristic drying equations. Bioactive compounds recovery from the leaves was examined under various parameters through a comparative approach that studied MAE against Soxhlet extraction. MAE of A. vasica reported similar yields although drastic reduction in extraction time (210 s) as against the average time of 10 h in the Soxhlet apparatus. Extract yield for MAE of C. citratus was higher than the conventional process with optimal parameters determined to be 20 g sample load, 1:20 sample/solvent ratio, extraction time of 150 s and 300 W output power. Scanning Electron Microscopy and Fourier Transform Infrared Spectroscopy were performed to depict changes in internal leaf morphology. © 2015 Faculty of Engineering, Alexandria University.

Alexandria Engineering Journal

Empirical modeling of drying kinetics and microwave assisted extraction of bioactive compounds from Adathoda vasica and Cymbopogon citratus

Closed-loop nutrient cycling is a simple, persuasive and elegant approach to realize efficient natural resource management, improved human well-being and long-term food security. In the spirit of sustainable sanitation through nutrient cycling, this study proposes a new pathway to realize resource recovery from anthropogenic waste fractions by the application of physico-chemical separation processes. Microwave Activated Carbon (MAC) prepared from coconut shells (agro-waste) were immobilized on etched glass bead supports and utilized within a continuous flow packed-bed column. Physical adsorption experiments were performed by passing human urine through the column to strip and recover more than 80% of the intrinsic urea. Backwashing of the column was performed to demonstrate the ease of urea-N desorption, reusability of MAC over multiple cycles and the reversible nature of the process. Further nutrient recovery was realized by dephosphatizing the column overflow with MgO to allow phosphate precipitation (&gt;90%) as struvite. Sorption kinetics, behaviour and influence of process parameters were studied by testing the experimental data against Yoon-Nelson, Thomas and Adams-Bohart models. The column adsorption was also numerically optimized using Response Surface Methodology to determine the optimal parameters as: sorbate flow rate - 8.5 L.h-1, urea concentration - 100%, support size - 1 cm and consequently, column capacity of 21.58 g. Nutrient recovery, concentration and recycling from diverted human urine can be seen as a synergistic and circular solution to the issues of sanitation, hygiene, water, and food security. © 2016 The Authors. Published by Elsevier Ltd.

Procedia Engineering

Nutrient Recovery and Recycling from Human Urine: A Circular Perspective on Sanitation and Food Security

Drying behavior of thin slabs of plaster of paris was investigated in microwave, convective and microwave assisted convective drier. The process parameters involved in the study include the microwave output power, air temperature used for drying, the initial moisture content of the sample, thickness and geometry of the sample. A typical drying profile, with no constant rate period followed by a falling rate period was obtained for all the three methodologies used. The mechanism of moisture movement within the sample during the falling period, as expressed by effective moisture diffusivity, was between 1.166×10-8 and 2.6927×10-8 (m2s-1) for the least microwave output power of 180W. The specific energy consumption and the drying efficiency involved in the microwave process, estimated from the energy supplied to the drier and the total time was found to be 0.4557MJkg-1 and 82.56% for a sample thickness of 0.013m. The microstructure of the fractured surfaces and qualitative phase analysis of microwave activated plaster of paris were extensively investigated by Scanning Electron Microscopy, Fourier Transform Infra-Red spectroscopy and X-Ray Diffraction techniques. The experimental moisture loss data with time was fitted to nine semiempirical thin layer equations. The suitability of the models was validated by comparing it with the predicted moisture ratio for any given set of operating conditions. The statistical analyses of the available literature correlations, for their applicability to the data of the present study showed greater deviation attributing their restricted range of applicability of individual correlations. As a result, a third order polynomial equation was developed from this study. © 2013 The Institution of Chemical Engineers.

Chemical Engineering Research and Design

Thin layer drying kinetics, characteristics and modeling of plaster of paris

Saudi Journal of Biological Sciences

Biodegradation of diesel fuel hydrocarbons by mangrove fungi from Red Sea Coast of Saudi Arabia

Chemical Engineering Science

Mathematical model for continuous and intermittent microwave-assisted extraction of bioactive compound from plant material: Extraction of β-carotene from carrot peels

Optimization of microwave-assisted extraction based on absorbed microwave power and energy

Pharmaceutical Biology

Seasonal variation of the main individual phenolics and juglone in walnut (Juglans regia) leaves

Influence of Microwave and Ultrasound pretreatment on Solvent Extraction of Bio-components from Walnut (Julgans regia L.) Shells

Journal	Periodica Polytechnica Chemical Engineering
Publisher	Periodica Polytechnica Budapest University of Technology and Economics
ISSN	0324-5853
Open Access	Yes