New Insights in the Treatment of Waste Water with Graphene: Dual-Site Adsorption by Sodium Dodecylbenzenesulfonate

Insertable, Scabbarded, and Nanoetched Silver Needle Sensor for Hazardous Element Depth Profiling by Laser-Induced Breakdown Spectroscopy

Sensing of hazardous metals is urgent in many areas (e.g., water pollution and meat products) as heavy metals threaten people's health. Laser-induced breakdown spectroscopy (LIBS), as a rapid, in situ, and multielemental analytical technique, has been widely utilized in rapid hazardous heavy metal sensing. However, loose and water-containing samples (e.g., meat, plant, and soil) are hard to analyze by LIBS directly, and heavy metal depth profiling for bulk samples remains suspenseful. Here, inspired by the Needle, the sword of Arya Stark in Game of Thrones, we propose an insertable, scabbarded, and nanoetched silver (NE-Ag) needle sensor for rapid hazardous element sensing and depth profiling. The NE-Ag needle sensor features a micro-nanostructure surface for inserting into the bulk sample and absorbing hazardous analytes. For accurate elemental depth profiling, we design a stainless-steel scabbard to wrap and protect the NE-Ag needle from pollution (unexpected contaminant absorption) during the needle insertion and extraction process. The results for cadmium (Cd) show that the relative standard deviation equals to 6.7% and the limit of detection reaches 0.8 mg/L (ppm). Furthermore, the correlations (Pearson correlation coefficient) for Cd and chromium (Cr) depth profiling results are no less than 0.96. Furthermore, the total testing time could be less than 1 h. All in all, the insertable and scabbarded NE-Ag needle senor has high potential in rapid hazardous heavy metal depth profiling in different industries.

One step forward: How can functionalization enhance the adsorptive properties of graphene towards metallic ions and dyes?

Functionalized graphene and its derivatives have been subject of many recent studies investigating their use as scavenger of various industrial pollutants. Adsorption is a feasible treatment, which can employ a wide variety of materials as adsorbents. Additionally, graphene has been distinguished for its remarkable properties, such as mechanical resistance, flexibility and electric conductivity. A relevant aspect of functionalized graphene is related to its selectivity, resulting in increased removal rates of specific pollutants. Hence, the functionalization process of graphene nanosheets is the cutting edge of the materials and environmental sciences, promoting the development of innovative and highly capable sorbents. The purpose of this review is to assemble the available information about functionalized graphene nanomaterials used for the removal of water pollutants and to explore its wide potential. In addition, various optimal experimental conditions (solution pH, equilibrium time, adsorbent dosage) are discussed. In each topic, aspects of environmental protection of adsorption process were evaluated, as well as the most recent works, available from high impact journals in the field, have been explored. Additionally, the employment of natural compounds to functionalize, reduce and support graphene, was evaluated as green alternatives to chemicals.

Recent Advances in Water Treatment Using Graphene-based Materials

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A variety of processes were reported for efficient removing of heavy metal from wastewater, including but not limited to ion exchange, reverse osmosis, membrane filtration, flotation, coagulation, chemical precipitation, solvent extraction, electrochemical treatments, evaporation, oxidation, adsorption, and biosorption. Among the aforementioned techniques, adsorption/ion exchange has been known as a most important method for removing heavy metal ions and organic pollutants due to great removal performance, simple and easy process, cost-effectiveness and the considerable choice of adsorbent materials.

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Nanotechnology and its applications have been developed in most branches of science and technology. Extensive studies have been conducted to remove heavy metal ions from wastewater by preparation and applications of various nanomaterials. Nanomaterials offer advantages in comparison to other materials including an extremely high specific surface area, low-temperature modification, short intraparticle diffusion distance, numerous associated sorption sites, tunable surface chemistry, and pore size. In order to evaluate an adsorbent, two key parameters are: the adsorption capacity and the desorption property. The adsorption parameters including the absorbent loading, pH and temperature, concentration of heavy metal ion, ionic strength, and competition among metal ions are often studied and optimized.

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Several reviews have been published on the application of Graphene (G), Graphene Oxide (GO) in water treatment. In this minireview, we attempted to summarize the recent research advances in water treatment and remediation process by graphene-based materials and provide intensive knowledge of the removal of pollutants in batch and flow systems. Finally, future applicability perspectives are offered to encourage more interesting developments in this promising field. This minireview does not include patent literature.

From n-butyl acrylate Arrhenius parameters for backbiting and tertiary propagation to β-scission via stepwise pulsed laser polymerization

A stepwise method to estimate the Arrhenius parameters for backbiting, tertiary propagation, and β-scission in acrylate radical polymerization.

Access to the β-scission rate coefficient in acrylate radical polymerization by careful scanning of pulse laser frequencies at elevated temperature

A novel method to estimate the β-scission rate coefficient in acrylate radical polymerization is presented.

A detailed mechanistic study of bulk MADIX of styrene and its chain extension

By combining experimental and modeling tools, a detailed characterization study of MADIX properties becomes possible.