https://digital.csic.es/bitstream/10261/78256/1/Microwave%20heating%20processes_JAMD_2010.pdf

Microwave heating processes involving carbon materials

Plant extracts have been long used by the traditional healers for providing health benefits and are nowadays suitable ingredient for the production of formulated health products and nutraceuticals. Traditional methods of extraction such as maceration, percolation, digestion, and preparation of decoctions and infusions are now been replaced by advanced extraction methods for increased extraction efficiency and selectivity of bioactive compounds to meet up the increasing market demand. Advanced techniques use different ways for extraction such as microwaves, ultrasound waves, supercritical fluids, enzymes, pressurized liquids, electric field, etc. These innovative extraction techniques, afford final extracts selectively rich in compounds of interest without formation of artifacts, and are often simple, fast, environment friendly and fully automated compared to existing extraction method. The present review is focused on the recent trends on the extraction of different bioactive chemical constituents depending on the nature of sample matrices and their chemical classes including anthocyanins, flavonoids, polyphenols, alkaloids, oils, etc. In addition, we review the strategies for designing extraction, selection of most suitable extraction methods, and trends of extraction methods for botanicals. Recent progress on the research based on these advanced methods of extractions and their industrial importance are also discussed in detail.

/pdf/a-critical-analysis-of-extraction-techniques-used-for-a6s9jnpt60.pdf

A critical analysis of extraction techniques used for botanicals: Trends, priorities, industrial uses and optimization strategies

In recent years, microwave (MW) irradiation has gained widespread popularity as an effective thermal method for sludge treatment, mainly due to its rapid and selective heating, energy efficiency, capacity to enhance the yield and quality of product and diminished hazardous product formation and emissions (thus rendering the technique environmentally friendly). The present review aspires to advance understanding of the versatile uses of the MW irradiation technique in sludge treatment, including sludge pretreatment and enhancement in the anaerobic biodegradability of waste sludge and sludge sanitisation, resources (bio-gas, bio-oil, nutrients and heavy metals) recovery and, heavy metals stabilisation. It also summarises future research directions for the better use of MW energy in sludge treatment, process optimisation and developments for industrial-scale implementation of the MW technique and, safety and health related issues.

Microwave irradiation: A sustainable way for sludge treatment and resource recovery

Self-powered cleaning of air pollution by wind driven triboelectric nanogenerator

Packed-bed plasma reactors, constructed by packing noncatalytic dielectric pellets inside nonthermal plasma reactors, have been demonstrated to effectively alleviate the major bottleneck encountered by nonthermal plasma, i.e., the energy efficiency needs to be further improved. As far as the environmental issues are concerned, packed-bed plasma reactors are mainly applied to ozone generation and gaseous pollutant removal. According to the available experimental data, for a given specific energy density, the energy efficiency for ozone generation and gaseous pollutant abatement obtained with packed-bed reactors, if compared to that of nonpacked reactors, could be 1.1−4.3 and 1.1−12 times higher, depending on the type of pollutant, the reactor geometry, and the packing pellets used. Nevertheless, it is worth noticing that the packing pellets suitable for ozone generation and pollutant removal are quite different. The influences of material, dielectric constant, size, and shape of the packing pellets on the ...

Review of Packed-Bed Plasma Reactor for Ozone Generation and Air Pollution Control

SO2 and NOx removal by electron beam and electrical discharge induced non-thermal plasmas

This study presents the effect of the polyfunctional monomers (PFMs) triallylcyanurate (TAC), triallylisocyanurate (TAIC), 
trimethylolpropane trimethacrylate (TMPT), ethylene glycol dimethacrylate (EDMA) and zinc diacrylate (ZDA) on the mechanical properties of natural rubber (NR) crosslinked by electron beam (EB) processing. Dependence of mechanical properties and crosslink density on irradiation dose was determined from a dose range of 50 to 200 kGy. The control blends, obtained with benzoyl peroxide as curing agent, were prepared by blending on a laboratory roller and the control sample curing was accomplished on hydraulic press at 160 °C. The results showed an increase in mechanical properties and crosslink density due to the introduction of PFMs. Also, based on the comparison between EB irradiation and dibenzoyl peroxide vulcanization efficiency, the experimental results show that EB irradiation gave the best results.

Radiation vulcanization of natural rubber with polyfunctional monomers

The obtaining and characterization of some polymeric eco-composites based on wood sawdust and natural rubber is presented. The natural rubber was cross-linked using the electron beam irradiation. The irradiation doses were of 75, 150, 300 and 600 kGy and the concentrations of wood sawdust were of 10 and 20 phr, respectively. As a result of wood sawdust adding, the physical and mechanical properties such as hardness, modulus at 100% elongation and tensile strength, showed significant improvements. The presence of wood sawdust fibers has a reinforcing effect on natural rubber, similar or better than of mineral fillers. An increase in the irradiation dose leads to the increasing of cross-link density, which is reflected in the improvement of hardness, modulus at 100% elongation and tensile strength of blends. The cross-linking rates, appreciated using the Flory-Rehner equation, have increased with the amount of wood sawdust in blends and with the irradiation dose. Even if the gel fraction values have varied irregularly with the amount of wood sawdust and irradiation dose it was over 90% for all blends, except for the samples without wood sawdust irradiated with 75 kGy. The water uptake increased with increasing of fiber content and decreased with the irradiation dose.

Wood Sawdust/Natural Rubber Ecocomposites Cross-Linked by Electron Beam Irradiation.

Application of accelerated electron beam and microwave irradiation to biological waste treatment

The goal of the paper was to prepare a class of flocculants by free-radical copolymerization of acrylamide with acrylic acid in aqueous solutions in the presence/absence of potassium persulphate as initiator. Reaction medium was submitted to electron beam treatment of 0.6 to 1.5 kGy in atmospheric conditions and at room temperature. Because of the complexity of reaction mechanisms involved in radio-induced polymerization, was necessary to establish the connection between absorbed dose and initiator concentration, both of them very important in free radical production. Unlike the conversion coefficient and residual monomer concentration, intrinsic viscosity and Huggin’s constant are sensitive to the initiator concentration variation for all used irradiation doses. The copolymerization was confirmed by FTIR measurements. The flocculation characteristics were evaluated in 0.2 wt % kaolin suspension at room temperature using different polymer dosages between 0 to 10 ppm. High flocculation efficiency was obtained using the polymer having high values of intrinsic viscosity, molecular weight and radius of gyration.

/pdf/synthesis-and-characterization-of-poly-acrylamide-co-acrylic-1hyrrxgn8t.pdf

Daniel Ighigeanu

Papers

SO2 and NOx removal by electron beam and electrical discharge induced non-thermal plasmas

Radiation vulcanization of natural rubber with polyfunctional monomers

Wood Sawdust/Natural Rubber Ecocomposites Cross-Linked by Electron Beam Irradiation.

Application of accelerated electron beam and microwave irradiation to biological waste treatment

Synthesis and Characterization of Poly(Acrylamide-Co-Acrylic Acid) Flocculant Obtained by Electron Beam Irradiation