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The unorganized dumping of effluents along with different wastes directly into the water and soil has resulted in the rise of the concentration of many harmful metals, chemicals, and other gases in the environment. Widely known heavy metals triggering pollution issues are Lead (Pb), Chromium (Cr), Mercury (Hg), Cadmium (Cd), Copper (Cu), Arsenic (As) and Selenium (Se), as these heavy metals are generally found in the effluents of fertilizers, metallurgy, electroplating, and electronics industries. A number of physical-chemical reactions such as acid-base, oxidation-reducing, precipitation- dissolution, solubilization and ion-exchange processes occur and affect metal speciation. The physical methods used for heavy metals removal include magnetic separation, electrostatic separation, mechanical screening method, hydrodynamic classification, gravity concentration, flotation, and attrition scrubbing. The chemical methods used for eliminating heavy metals are chemical precipitation, coagulation and flocculation processes and the heavy metals are therefore removed as sludge. Electro-deposition, membrane filtration, electro-flotation and electrical oxidation are the various electrochemical treatment methods that are used to remove heavy metals from wastewater. Bioremediation is a biological method of eliminating toxins from the environment by using biological microbial bacteria such as Pseudomonas and Sphingomonas. Examples of bioremediation technologies include field farming, bioleaching, phytoremediation, bioventing, bioreactor, bio-stimulation and composting. Bioremediation is a natural process and is quite applicable as a waste treatment process for contaminated soils. The microbes present in the solution or soil can degrade the pollutants. It can also prove to be less expensive than other technologies that are used for clean-up of hazardous waste and are also useful for the destruction of a wide variety of contaminants as many hazardous compounds can be transformed into harmless products.

Background: Kraton/polyaniline ionomer is synthesized and further characterized by electrochemical studies to check the redox properties of the material. Ion exchange capacity, proton conductivity, and selectivity of the synthesized membrane were determined. And found that the membrane was selective for Cu (II) ions. Methods: The dry Kraton membranes were weighed and kept in 25 mL of 10 % prepared aniline solution in a conical flask for 5, 10, 15, and 20 minutes below 10 0C for socking. The prepared solution of 30 mL of 0.1 M potassium peroxydisulfate was added in a conical flask at constant stirring below 10 0C for half an hour. Finally, the aluminum foil-covered conical flask was kept in the refrigerator for 24 h and modified Kraton membranes were weighed again before carrying out further studies. Results: The membrane was characterized by some physicochemical methods like SEM, TGA, T-IR, IEC, proton conductivity and selectivity sorption studies. An ionomeric membrane of Kraton polymer was developed as reported earlier. Kraton membrane showed the IEC of 1.9 meq·g-1. The FTIR spectrum of Kraton/PANI film reveals that weight loss up to 400°C may be found because of the thermal degradation of composite substances. Conclusion: Ion-selective potentiometric was carried out using the self-prepared ion-selective membrane electrode. The membrane was prepared by solution casting method. The membrane was characterized by some physicochemical methods like SEM, TGA, T-IR, IEC, proton conductivity and selectivity sorption studies. On the basis of selectivity studies, the composite material was found selective for Cu (II) ion. A copper ISME was successfully fabricated using the solution casting method. The ISME possessed good selectivity, linearity, working pH range, and response time which was also used as an indicator electrode for the titration of copper using EDTA.

The FeZnO (iron zinc bimetallic oxide) was synthesised using the ultrasound-assisted method and further converted into FeZnOAC (iron zinc bimetallic oxide-doped activated carbon) by treating it with activated carbon. As developed FeZnOAC is effectively used for the adsorption of Fuchsine dye from an aqueous dye solution. A 200 mg of FeZnOAC was sufficient for the rapid removal of Fuchsine (>97.64%) dye. The kinetic adsorption data is well fitted with a pseudo-second-order model. The Langmuir isothermal model shows a high regression coefficient (R2) than the Freundlich with a Qmax of 333.33 mg g−1. The dye adsorption at varying temperatures (i.e. 298–318 K) was based on a multi-layered statistical physics model. The n value (n

Background: Nanoparticles have become an important part of many modern scientific technologies. Also, many naturally occurring nanoparticles play an important role in various natural and synthetic processes. The detection of these nanoparticles is expensive and challenging. This review paper explains in detail about various sensor-based methods used for the detection of nanoparticles. Methodology: Sensor-based analytical techniques are more accurate than other techniques. Nanoparticles may occur in air, water, solid surface and human or other living organisms’ physical environments. The detection methods include spectroscopic techniques, electrochemical methods, microcavities and microlasers based detection, optical techniques and many other highly sensitive methods. All these methods and their principles are explained in this study. The importance and the ill effects of the nanoparticles are explained in this article. Further, the detection of a particular single nanoparticle is also discussed. Conclusions: The detailed comparative analysis of these methods has shown that sensor-based methods are highly efficient for the detection of nanoparticles. Further research in this field may introduce many cost-effective and high efficient detection techniques that would revolutionize the medical and other application fields.

The prospective of this work is to synthesize a new nanocomposite that serves as an electrode material for the immobilization of biomolecules. In this work surface-functionalized single-walled carbon nanotubes (f–COOH–SWCNTs), and hydrothermally synthesized surface defected 2D nanoplates wrapped by polpyrrole matrix was developed. The developed nanocomposite was utilized as the anode material for the immobilization of enzymes. Nanocomposite f-SWCNTs@Ppy@NiMoSe2 was characterized by X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and the electrochemical methods including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and linear sweep voltammetry (LSV). The electrochemically controlled bioanode reached to the open circuit potential (OCV) of 0.35 V and delivered the maximum current density of 9.01 mA cm−2 in 50 mM glucose concentration prepared in phosphate buffer solution (PBS) (pH 7.0) as the testing solution at 100 mVs−1 scan rates.

Fischer-Tropsch (FT) process has great potential to accomplish energy security but also for utilizing greenhouse gases to address the energy problem. Different kinds of feedstocks like coal, biomass (via gasification), CO2, methane (via reforming), and nonconventional energy sources are used to obtain the syn-gas (CO and H2). The formation of hydrocarbons in the FT process follows ASF distribution over the majority of the catalysts. It can be overcome by the application of a suitable catalyst, controlling the active metal interaction with the support and interaction of formed hydrocarbon with the support. The ratio of syn-gas is important to maintain the desired conversion and to have more selectivity towards C5+ products. Increase in the H2: CO ratios in the feed increases C5+ products and methane decreases. Whereas with the decrease in the ratios increases undesirable reactions and methane formation. In this article, we have discussed the recent literature from the viewpoint of increasing the C5+ selectivity. Support has a profound influence on product distribution. With the application of suitable support and controlling the interaction of the active sites yields the good CO conversion with fewer lighters and higher C5+ hydrocarbons.

Colorimetric and ratiometric fluorescent probe for cations gain very well attention by the chemist, biologist and environmentalist. Metals has two sides, first is biolgical active for living creature and toxic nature for the ecosystem. From last three decades the scientists are contiously trying to find out the best solution for the detection of cations at micro as well as nanomolar levels. In the present review we discussed the colorimetric and ratiometric fluorescent probe synthesized by the authors in almost half decade.

Many materials used in energy devices or applications suffer from the problem of electron–hole pair recombination. One promising way to overcome this problem is the use of heterostructures in place of a single material. If an electric dipole forms at the interface, such a structure can lead to a more efficient electron–hole pair separation and thus prevent recombination. Here we model and study a heterostructure comprised of two polymorphs of Fe2O3. Each one of the two polymorphs, α-Fe2O3 and e-Fe2O3, individually shows promise for applications in photoelectrochemical cells. The heterostructure of these two materials is modeled by means of density functional theory. We consider both ferromagnetic as well as anti-ferromagnetic couplings at the interface between the two systems. Both individual oxides are insulating in nature and have an anti-ferromagnetic spin arrangement in their ground state. The same properties are found also in their heterostructure. The highest occupied electronic orbitals of the combined system are localized at the interface between the two iron-oxides. The localization of charges at the interface is characterized by electrons residing close to the oxygen atoms of e-Fe2O3 and electron–holes localized on the iron atoms of α-Fe2O3, just around the interface. The band alignment at the interface of the two oxides shows a type-III broken band-gap heterostructure. The band edges of α-Fe2O3 are higher in energy than those of e-Fe2O3. This band alignment favours a spontaneous transfer of excited photo-electrons from the conduction band of α- to the conduction band of e-Fe2O3. Similarly, photo-generated holes are transferred from the valence band of e- to the valence band of α-Fe2O3. Thus, the interface favours a spontaneous separation of electrons and holes in space. The conduction band of e-Fe2O3, lying close to the valence band of α-Fe2O3, can result in band-to-band tunneling of electrons which is a characteristic property of such type-III broken band-gap heterostructures and has potential applications in tunnel field-effect transistors.