Green Chemistry is a relatively new emerging field that strives to work at the molecular level to achieve sustainability. The field has received widespread interest in the past decade due to its ability to harness chemical innovation to meet environmental and economic goals simultaneously. Green Chemistry has a framework of a cohesive set of Twelve Principles, which have been systematically surveyed in this critical review. This article covers the concepts of design and the scientific philosophy of Green Chemistry with a set of illustrative examples. Future trends in Green Chemistry are discussed with the challenge of using the Principles as a cohesive design system (93 references).

Green Chemistry: Principles and Practice

Antibacterial activity of zinc oxide nanoparticles (ZnO-NPs) has received significant interest worldwide particularly by the implementation of nanotechnology to synthesize particles in the nanometer region. Many microorganisms exist in the range from hundreds of nanometers to tens of micrometers. ZnO-NPs exhibit attractive antibacterial properties due to increased specific surface area as the reduced particle size leading to enhanced particle surface reactivity. ZnO is a bio-safe material that possesses photo-oxidizing and photocatalysis impacts on chemical and biological species. This review covered ZnO-NPs antibacterial activity including testing methods, impact of UV illumination, ZnO particle properties (size, concentration, morphology, and defects), particle surface modification, and minimum inhibitory concentration. Particular emphasize was given to bactericidal and bacteriostatic mechanisms with focus on generation of reactive oxygen species (ROS) including hydrogen peroxide (H2O2), OH− (hydroxyl radicals), and O2 −2 (peroxide). ROS has been a major factor for several mechanisms including cell wall damage due to ZnO-localized interaction, enhanced membrane permeability, internalization of NPs due to loss of proton motive force and uptake of toxic dissolved zinc ions. These have led to mitochondria weakness, intracellular outflow, and release in gene expression of oxidative stress which caused eventual cell growth inhibition and cell death. In some cases, enhanced antibacterial activity can be attributed to surface defects on ZnO abrasive surface texture. One functional application of the ZnO antibacterial bioactivity was discussed in food packaging industry where ZnO-NPs are used as an antibacterial agent toward foodborne diseases. Proper incorporation of ZnO-NPs into packaging materials can cause interaction with foodborne pathogens, thereby releasing NPs onto food surface where they come in contact with bad bacteria and cause the bacterial death and/or inhibition.

/pdf/review-on-zinc-oxide-nanoparticles-antibacterial-activity-2smaigi8sc.pdf

Review on Zinc Oxide Nanoparticles: Antibacterial Activity and Toxicity Mechanism.

https://eva.fing.edu.uy/pluginfile.php/55828/mod_resource/content/1/kalogiru.pdf

Solar thermal collectors and applications

An introduction to heat transfer

Band bending in semiconductors: chemical and physical consequences at surfaces and interfaces.

This paper presents a review of the organic Rankine cycle and supercritical Rankine cycle for the conversion of low-grade heat into electrical power, as well as selection criteria of potential working fluids, screening of 35 working fluids for the two cycles and analyses of the influence of fluid properties on cycle performance. The thermodynamic and physical properties, stability, environmental impacts, safety and compatibility, and availability and cost are among the important considerations when selecting a working fluid. The paper discusses the types of working fluids, influence of latent heat, density and specific heat, and the effectiveness of superheating. A discussion of the 35 screened working fluids is also presented.

A review of thermodynamic cycles and working fluids for the conversion of low-grade heat

Thermal energy storage technologies and systems for concentrating solar power plants

1. Introduction to Solar Energy Conversion 2. Fundamentals of Solar Radiation 3. Methods of Solar Collection and Thermal Conversion 4. Thermal Energy Storage and Transport 5. Solar-Heating Systems 6. Solar Cooling and Dehumidification 7. Passive Methods for Heating, Cooling and Daylighting 8. Solar Thermal Power and Process Heat 9. Photovoltaics 10. Solar Photochemical Applications 11. Capturing Solar Energy through Biomass 12. Introduction to Economic Analysis

Principles of solar engineering

This paper is a review of the fundamental disinfection mechanisms of photocatalysis and the models used to fit the disinfection process. Photocatalysis is an attractive technology for water treatment largely due to its potential to utilize solar energy directly and achieve both disinfection and chemical detoxification. Many papers have been published on photocatalytic disinfection, but there is still considerable debate on disinfection mechanisms and a general lack of mechanistic models for the process. The fundamental photocatalytic disinfection mechanisms as they relate to the inactivation of bacteria are comprehensively surveyed here. The process of lipid peroxidation of membrane fatty acids, particularly polyunsaturated fatty acids, is gaining momentum in the literature. In recent papers, an increasing number of researchers are paying close attention to the products of lipid peroxidation. The mathematical models, empirical and mechanistic, used to fit the disinfection process have also been thoroughly reviewed. In this regard, most of the proposed models are empirical in nature and rooted in traditional chemical disinfection principles, which are often not representative of the heterogeneous photocatalytic process. The theoretical development of a mechanistic model for photocatalytic disinfection based on lipid peroxidation is explored with due consideration to the interaction between microbes and photocatalyst particles. The extensive literature on autooxidation of lipids in such fields as biology and medicine is informative to the development of the model.

A review of the mechanisms and modeling of photocatalytic disinfection

ZnO nanowires (or nanorods) have been widely studied due to their unique material properties and remarkable performance in electronics, optics, and photonics. Recently, photocatalytic applications of ZnO nanowires are of increased interest in environmental protection applications. This paper presents a review of the current research of ZnO nanowires (or nanorods) with special focus on photocatalysis. We have reviewed the semiconducting photocatalysts and discussed a variety of synthesis methods of ZnO nanowires and their corresponding effectiveness in photocatalysis. We have also presented the characterization of ZnO nanowires from the literature and from our own measurements. Finally, a wide range of uses of ZnO nanowires in various applications is highlighted in this paper.

/pdf/synthesis-characterization-and-applications-of-zno-nanowires-1a5kdv4lbi.pdf

D. Yogi Goswami

Papers

A review of thermodynamic cycles and working fluids for the conversion of low-grade heat

Thermal energy storage technologies and systems for concentrating solar power plants

Principles of solar engineering

A review of the mechanisms and modeling of photocatalytic disinfection

Synthesis, characterization, and applications of ZnO nanowires