Micromachining technology was used to prepare chemical analysis systems on glass chips (1 centimeter by 2 centimeters or larger) that utilize electroosmotic pumping to drive fluid flow and electrophoretic separation to distinguish sample components. Capillaries 1 to 10 centimeters long etched in the glass (cross section, 10 micrometers by 30 micrometers) allow for capillary electrophoresis-based separations of amino acids with up to 75,000 theoretical plates in about 15 seconds, and separations of about 600 plates can be effected within 4 seconds. Sample treatment steps within a manifold of intersecting capillaries were demonstrated for a simple sample dilution process. Manipulation of the applied voltages controlled the directions of fluid flow within the manifold. The principles demonstrated in this study can be used to develop a miniaturized system for sample handling and separation with no moving parts.

Micromachining a miniaturized capillary electrophoresis-based chemical analysis system on a chip

https://cyberleninka.org/article/n/638974.pdf

Characteristics and adsorption capacities of low-cost sorbents for wastewater treatment: A review

Biomass is considered to have potential to be used as an alternative energy source. High carbon content present in biomass converts it into high energy biochar on thermochemical treatment. Among few well established thermochemical technologies for the treatment of biomass and biogenic waste to produce high energy char along with oil and gaseous yield, pyrolysis is the most studied and discussed technique in the recent past. A comparison between the existing techniques is established in the present work. Production of char from the biomass and biogenic wastes is reviewed and it was found that yield of the biochar depends upon the biomass composition like moisture content and presence of cellulose or lignin. Pyrolysis product distribution and their quality strongly depend upon the process parameters. Different biomasses which can be used as raw material in pyrolysis are also reviewed and categorized depending upon their source. Pyrolysis process parameters such as temperature, heating rate, residence time etc. also influence the biochar yield. This study discusses the effect of these process parameters on the production of biochar through pyrolysis of biomass.

Effect of process parameters on production of biochar from biomass waste through pyrolysis: A review

Graphitic carbon nitride (g-C3N4) has gained remarkable acceptance as a visible-light-driven photocatalyst with a distinctive 2D structure and great stability. Owing to its superior features, g-C3N4 has been engaged in various scientific activities for environmental pollution abatement, production and storage of energy, and gas sensors. However, the visible-light efficiency of pure g-C3N4 is very poor and its separation from the phototreated systems is difficult. The most promising method to improve the photocatalytic activity and facilitate separation process is to introduce a magnetic compound over the g-C3N4 sheets. This review has mainly focused on the recent advancement in fabrication, characterization and application of magnetic g-C3N4-based nanocomposites. Accordingly, four primary g-C3N4-based nanocomposites are discussed based on the type of integrated magnetic material. The effects on the structure, physico-chemical properties, photocatalytic activity towards degradation of pollutants, hydrogen generation, solid phase extraction, lithium-ion batteries, gas sensors, and supercapacitors are also discussed in detail.

Review on magnetically separable graphitic carbon nitride-based nanocomposites as promising visible-light-driven photocatalysts

Among the most challenging problems that human beings appear to face are depleting energy sources and increasing environmental pollutions. Heterogeneous photocatalytic processes are the most reward...

Magnetically separable nanocomposites based on ZnO and their applications in photocatalytic processes: A review

Industries generating wastewater with elevated concentrations of pollutants (e.g. metals, dyes, phenolic compounds, anions, etc.) need specialized atreatment systems. Adsorption is one of the most extensively applied techniques for the removal of pollutants from the industrial effluents. The prominent and emerging trend of subjecting biosorbent in the adsorption technology is mainly because of their natural existence, abundance, renewable, biodegradable and economic features. The adsorption isotherm equations used to describe the experimental data and the thermodynamic assumptions of the models often provide some insight into the sorption mechanism, the surface properties and affinity of the biosorbent. This paper presents a state of the art on the review of adsorption isotherm models in an exhaustive manner on the basis of two, three, four and five parameters respectively. Focuses on the various sources of agricultural byproducts as biosorbents and describes on the potential applications of different adsorption isotherm models for the evaluation of the wastewater pollutants biosorption. It is evident from the literature survey that various adsorption isotherm models have been considered under study by the researchers but mostly two and three parameter isotherm model were best fitted the equilibrium data. This paper reviews the adsorption isotherm models on the basis of parameters that can be applied for exploring a novel biosorbents.

Relevance of isotherm models in biosorption of pollutants by agricultural byproducts

Agricultural wastes products are quite commonly distributed as the result of agricultural practices. They are inexpensive and subject to biodegradable. Agricultural waste is a good source for the adsorption of the dyes generated during the textile processing. For the process of adsorption, agricultural waste products are used as natural or in the modified form through activation process. This review article focuses on the various sources of the agricultural waste products and its adsorption capacity of the different dyes. Signifying the potential of the use of agricultural wastes products for removing off the toxic dye substances from the effluent discharging into the water bodies.

Sequestration of dye from textile industry wastewater using agricultural waste products as adsorbents

Adsorptive remediation of hexavalent chromium from synthetic wastewater by a natural and ZnCl2 activated Sterculia guttata shell

The present study was undertaken in order to evaluate the feasibility of a novel biosorbent Caryota urens inflorescence waste biomass (CUIWB) for the removal of hexavalent chromium from aqueous solutions. The biosorbent was characterized by SEM, FT-IR spectral and EDS analysis. Biosorption studies were carried out as a function of pH, initial Cr(VI) concentration, biosorbent size, biosorbent dosage, agitation speed and temperature. It was found that the biosorption capacity of CUIWB depends on solution pH, maximum biosorption capacity for Cr(VI) was observed at pH 2. The isotherm models like Langmuir, Freundlich, Dubinin–Radushkevich, Elovich, Redlich–Peterson, Sips, Koble–Corrigan were used to analyze the equilibrium data. Langmuir and Redlich–Peterson model better fitted the equilibrium data. The biosorption capacity obtained using Langmuir isotherms for Cr(VI) biosorption was 100 mg/g. Kinetic study was performed using pseudo-first-order, pseudo-second-order and intraparticle diffusion models, but higher degree of coefficient of determination was obtained for the pseudo-second-order kinetic model. Different thermodynamic parameters, viz., Δ G °, Δ H ° and Δ S ° have also been evaluated and it has been found that the biosorption was spontaneous at low Cr(VI) concentration (100 and 200 mg/L), endothermic and increased randomness in nature, respectively. Desorption study was carried out with 0.1 M NaOH solutions. Investigations carried out proved that CUIWB is a good potential biosorbent for the treatment of hexavalent chromium in aqueous media.

Evaluation of the biosorption potential of a novel Caryota urens inflorescence waste biomass for the removal of hexavalent chromium from aqueous solutions

N. Selvaraju

Papers

Relevance of isotherm models in biosorption of pollutants by agricultural byproducts

Sequestration of dye from textile industry wastewater using agricultural waste products as adsorbents

Adsorptive remediation of hexavalent chromium from synthetic wastewater by a natural and ZnCl2 activated Sterculia guttata shell

Evaluation of the biosorption potential of a novel Caryota urens inflorescence waste biomass for the removal of hexavalent chromium from aqueous solutions

Efficacy of unmodified and chemically modified Swietenia mahagoni shells for the removal of hexavalent chromium from simulated wastewater