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a b s t r a c t a r t i c l e i n f oCovalent bulk modification of multiwalled carbon nanotubes using Fast Violet B salt containing potential donor atoms towards mercury is described. The chemically modified CNTs were characterized by FTIR and XPS techniques. The aqueous colloidal solution of modified CNTs was used in the construction of electrochemical interface for the determination of mercury at picomolar level. The analytical utility of the proposed sensor has been validated by estimating the mercury content in real sample matrices like drinking water and industrial effluent samples.

Background: We synthesized cerium oxide (CeO2) nanoparticles (NPs) via green synthesis method mediated with Rajma seeds powder as a fuel and cerium nitrate as an oxidizer. Objective: The obtained cerium oxide nanoparticles are used to study the various environ mental appilications. Methods: The achieved CeO2 nanoparticles are tested using PXRD (Powder X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), electron microscopic studies including SEM, Raman spectroscopy, UV-Visible spectroscopy. Formation of agglomerated cubic phased CeO2 nanoparticles were confirmed from both PXRD and SEM. Results: The average crystallite size of CeO2 nanoparticles was found to be 38 nm calculated from highly intense peak using Debye-Scherer’s formula. The characteristic Ce-O stretching was confirmed by FTIR and Raman studies. CeO2 nanoparticles are promising material for the organic dye degradation. Photocatalytic activities evaluation under various parameters like sunlight, UV light and variation of PH, catalytic dosage etc. CeO2 nanoparticles exhibit highly enhanced photo degradation of Methylene Blue dye. Kinetics and isotherm models of Photocatalysis were studied. Conclusion: We have prepared CeO2 nanoparticles by low-temperature combustion technique using Rajma germinated and Rajma non- germinated seeds as fuel. The XRD pattern confirms the formation of cubicphase CeO2 nanoparticles. The existence of Ce-O vibration is confirmed by FTIR and Raman spectra of the CeO2 nanoparticles. The UV-Visible spectra of CeO2 nanoparticles reveal the absorbance band range at 350-390 nm. SEM images of CeO2 nanoparticles indicates the agglomerated with irregular morphology. CeO2 nanoparticles are favorable material for the organic Methylene blue dye degradation. The different amount of the Rajma influences improved Photodegradation of cerium oxide nanoparticles was characteristics of slight crystal dimension, new superficial deficiencies, more band hole and ability to make smaller the electron-hole pair rearrangement. Adsorption kinetics results show that adsorption of MB over cerium oxide follows pseudo-first-order and second-order kinetics. Using the Langmuir isotherm, Freundlich isotherm, maximum adsorption capacity is calculated. Thus it can be used as attractively recoverable nano adsorbent for the removal of MB dye by adsorption technique from effluent water.

a b s t r a c tA new type of covalent binderless bulk modified electrode has been fabricated and used in the simultaneous determination of lead and cadmium ions at nanomolar level. The modification of graphitic carbon with 4-amino salicylic acid was carried out under microwave irradiation through the amide bond formation. The electrochemical behavior of the fabricated electrode has been carried out to decipher the interacting ability of the functional moieties present on the modifier molecules toward the simultaneous determination of Pb 2+ and Cd 2+ ions using cyclic and differential pulse anodic stripping voltammetry. The possible mode of interaction of functional groups with metal ions is proposed based on the pKa values of the modifier functionalities present on the surface of graphitic carbon particles. The analytical utility of the proposed sensor has been validated by measuring the lead and cadmium content from pretreated waste water samples of lead acid batteries.

a b s t r a c tA sensitive and selective electrochemical sensing platform for mercury quantification at picomolar level has been described. The interface was constructed using exfoliated graphitic carbon covalently functionalized with mercaptobenzothiozole (MBT) as a selective indicator species in mercury determination. It was characterized using Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV) techniques and subsequently used in the fabrication of surface renewable binderless bulk modified robust pellet electrode. The fabricated electrode was used in the measurement of mercury in alkaline medium using differential pulse anodic stripping voltammetry (DPASV). The developed interface showed linearity in the concentration range 1-20 pM with a detection limit of 1 pM. The analytical utility of the proposed interface has been validated by determining the mercury levels from various water and industrial effluent samples with least interference from commonly encountered cations and anions that are generally present in industrial effluents. The storage stability of the proposed interface has been studied over a period of 6 months and the results were found to be highly reproducible with a relative standard deviation of ±6%.

a b s t r a c tA simple and green chemistry protocol has been proposed based on the covalent anchoring of benzamide molecule on glassy carbon spheres through ball milling under solvent free condition. The modification proceeds through the formation of an amide bond between carboxylic group of glassy carbon spheres and the amino group of modifier molecule. The formation of covalent bond was ascertained using X-ray photoelectron spectroscopy. Scanning electron microscopy was used to study the surface morphology of milled glassy carbon spheres. The aqueous colloidal solution of modified glassy carbon spheres was used in the preparation of thin film electrodes and subsequently used as a novel electrochemical interface in the quantification of mercury at trace level using a differential pulse anodic stripping voltammetric technique. The modified electrode showed good sensitivity and selectivity towards mercury with a detection limit of 1 nM with least interference from most of the ions. The analytical utility of the proposed electrode has been validated by determining the mercury levels in number of sample matrices.

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In the present work, an ease and green chemical protocol for the formation of polyaniline - Sn composite is proposed. The protocol involves the formation of composite by the simple mixing of tin nitrate and aniline at room temperature without using any agents for polymerisation process. The composite obtained has been well characterized with the aid of SEM with EDAX and XRD. Further, it has been used in the development of thin film electrodes on the surface of rigid glassy carbon electrode and subsequently employed as an electrochemical interface for the electroanalytical amperometric sensing of hydrazine model analyte system at trace concentration level. The developed interface showed good affinity towards the analyte in the dynamic range upto 400 µM with a detection limit of 0.1 µM (3ϭ). The stability, reproducibility has been proven to be good without any deviation in its electrochemical performance with least interference from commonly encountered foreign species. Finally, the practical utility of the developed sensor has been shown by determining the trace concentration levels of hydrazine from tap water.