Efficient Rice-Husk-Derived Silica Nanocatalysts for Organic Dye Removal from Water

Rice is the second most extensively consumed food ingredient, and its by-products in the paddy field include rice husk and straw. Rice husk ash, resulting from rice husk burning, is considered an environment menace, inducing negative effects on the area in which it is disposed of. In this study, rice husk was applied as a silicate source to obtain mesoporous silica material. Characterization techniques confirmed the well-ordered mesophase and resemblance of mesoporous silica resulting from rice husk ash with one obtained from conventional silica sources. The mesoporous silica material was further used as catalyst support. The resulting catalysts were used for rhodamine 110 oxidation, proving high potential for oxidizing hazardous organic compounds, such as dyes from water, resulting in environmentally harmless products.

Agricultural Waste As Silica Source In Tio2/Sio2 Synthesis For Photocatalytic Degradation Of Dye Compounds

Titanium dioxide (TiO2) is one of semiconductor material which has been used as photocatalyst that has very good potency to oxidize some hazardous organic compounds like dye waste, medical and pharmacological waste, and etc. Although TiO2 has high oxidation capacity for photocatalytic degradation, it has some deficiencies which can limit its application as photocatalyst. Those deficiencies are TiO2 is easily agglomerated, its charge carrier is conveniently formed as recombination, and it has low surface area. This article provides a review of a composite which consists of TiO2 as the dispersed phase and SiO2 as the matrix, this composite has better photacatalytic performance than TiO2 itself. SiO2 can increase the surface area of TiO2, prevent the agglomeration of TiO2 particle, and avoid the recombination of TiO2’s charge carrier. Consequently, it can improve the ability of TiO2 to do photocatalytic degradation. Agricultural wastes that consist of high silica content is potentially used as the resource of SiO2 in this composite and biosilica that is produced from natural waste has biocompatible and biodegradable properties. This article also provides it’s application for various dye photocatalytic degradation.

Recent Trends in the Development of Green Microextraction Techniques for the Determination of Hazardous Organic Compounds in Wine

Background:The sample preparation is the most crucial step in the analytical method development. Taking this into account, it is easily understood why the domain of sample preparation prior to detection is rapidly developing. Following the modern trends towards the automation, miniaturization, simplification and minimization of organic solvents and sample volumes, green microextraction techniques witness rapid growth in the field of food quality and safety. In a globalized market, it is essential to face the consumers need and develop analytical methods that guarantee the quality of food products and beverages. The strive for the accurate determination of organic hazards in a famous and appreciated alcoholic beverage like wine has necessitated the development of microextraction techniques.Objective:The objective of this review is to summarize all the recent microextraction methodologies, including solid phase extraction (SPE), solid phase microextraction (SPME), liquid-phase microextraction (LPME), dispersive liquid-liquid microextraction (DLLME), stir bar sorptive extraction (SBSE), matrix solid-phase dispersion (MSPD), single-drop microextraction (SDME) and dispersive solid phase extraction (DSPE) that were developed for the determination of hazardous organic compounds (pesticides, mycotoxins, colorants, biogenic amines, off-flavors) in wine. The analytical performance of the techniques is evaluated and their advantages and limitations are discussed.Conclusion:An extensive investigation of these techniques remains vital through the development of novel strategies and the implication of new materials that could upgrade the selectivity for the extraction of target analytes.

The Spatial Distribution of the Microbial Community in a Contaminated Aquitard below an Industrial Zone

The industrial complex Neot Hovav, in Israel, is situated above an anaerobic fractured chalk aquitard, which is polluted by a wide variety of hazardous organic compounds. These include volatile and non-volatile, halogenated, organic compounds. In this study, we characterized the indigenous bacterial population in 17 boreholes of the groundwater environment, while observing the spatial variations in the population and structure as a function of distance from the polluting source. In addition, the de-halogenating potential of the microbial groundwater population was tested through a series of lab microcosm experiments, thus exemplifying the potential and limitations for bioremediation of the site. In all samples, the dominant phylum was Proteobacteria. In the production plant area, the non-obligatory organo-halide respiring bacteria (OHRB) Firmicutes Phylum was also detected in the polluted water, in abundancies of up to 16 %. Non-metric multidimensional scaling (NMDS) analysis of the microbial community structure in the groundwater exhibited clusters of distinct populations following the location in the industrial complex and distance from the polluting source. Dehalogenation of halogenated ethylene was demonstrated in contrast to the persistence of brominated alcohols. Persistence is likely due to the chemical characteristics of brominated alcohols, and not because of the absence of active de-halogenating bacteria.

Removal of Organic Pollution in the Water Environment

The development of civilization entails a growing demand for consumer goods. A side effect of the production and use of these materials is the production of solid waste and wastewater. Municipal and industrial wastewater usually contain a large amount of various organic compounds and are the main source of pollution of the aquatic environment with these substances. Therefore, the search for effective methods of wastewater and other polluted water treatment is an important element of caring for the natural environment. This Special Issue contains nine peer-review articles presenting research on the determination and removal of environmentally hazardous organic compounds from aqueous samples. The presented articles were categorized into three major fields: new approaches to the degradation of water pollutants, new methods of isolation and determination of the emerging organic contaminants (EOCs), and the occurrence of EOCs in the water environment. These articles present only selected issues from a very wide area, which is the removal of organic pollution in water environment, but can serve as important references for future studies.