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The work herein describes the electrochemical detection of heavy metal ions, specifically cadmium and lead. The introduction and modification of functional groups such as Schiff bases leads to an enhanced sensitivity of the electrode to analytes. In this study, a platinum electrode has, for the first time, been modified with poly(3,4-ethylenedioxythiophene) (PEDOT/Schiff base) in CH2Cl2 containing Bu4NPF6 to detect cadmium(II) and lead(II) ions. The structures and morphologies of the polymer coatings were characterised via Fourier transform infrared spectroscopy and scanning electron microscopy, respectively. The electrochemical synthesis and redox state response in monomer-free synthesised films have been studied via cyclic voltammetry. Moreover, the effect of scan rate on the electrochemical behaviour of the modified electrodes was also studied. The voltammetric findings have been used to calculate the surface coverage required for the polymer films and the stability of polymer electrodes in the monomer-free solutions. Square wave voltammetry was applied for the determination of cadmium(II) and lead(II) ion concentrations and to assess the effects of pH on aqueous samples. The limits of detection for the modified electrode for cadmium(II) and lead(II) were found to be 0.95 μg L−1 and 1.84 μg L−1, respectively. These findings revealed that modified films can be considered good candidates for application in electrochemical detection devices.

The use of additives to modulate metal electrodeposition from deep eutectic solvents has, to date, apparently been of little interest given the dearth of such studies in the literature. Here, we have actively investigated the effects of nicotinic acid (NA) on the electrodeposition of copper in a choline chloride (ChCl)-ethylene glycol (EG)-based deep eutectic solvent (DES), (1ChCl:2EG), considered a “green solvent” due to its physiochemical properties. Bright copper deposits were formed when NA was added to the Cu electrolyte, while a dull Cu deposit was produced in its absence. New Cu species were found to have formed in the 1ChCl:2EG-based liquid when NA was added to the electrolyte. A number of analytical techniques, in this instance cyclic voltammetry, chronoamperometry, and chronocoulometery, have been employed to determine the various electrochemical properties, nucleation mechanisms, and kinetics of the Cu species reported herein. The diffusion coefficient for the Ethaline-Cu system was found to be affected by the concentration of NA. An electrochemical quartz crystal microbalance (EQCM) was used to monitor the current efficiency of the copper deposition in both systems. The morphologies, thicknesses, roughnesses, and crystal structures of the copper electrodeposited from the NA-modified electrolyte were characterised via scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD), which between them demonstrate that the NA introduced into this system acts as a highly effective brightener, producing highly uniform and smooth copper deposits.

The effects of nicotinic acid (NA), boric acid (BA) and benzoquinone (BQ) on the electrodeposition of Zn have been studied in a choline chloride (ChCl) ethylene glycol (EG) based deep eutectic solvent (DES), (1ChCl:2 EG), and for the first time a bright zinc coating has been achieved when NA was used. In metal electroplating processes, small-molecule additives are often included in the plating bath to improve properties of coating such as brightness, roughness, thickness, hardness and resistance to corrosion. The effects of additives on the electrodeposition of Zn from aqueous solution have been extensively investigated. However, very few studies have considered the effects of additives on the electrodeposition of Zn from ionic liquids or deep eutectic solvents. The electrochemical properties of the plating liquid have been studied here using cyclic voltammetry, chronocoulometry, chronoamperometry and microgravimetry (EQCM). Redox peak currents decrease when additives were included in the Zn solution and total charge was also reduced in experiments where additives were present. The Zn deposition in the absence of additive is in good agreement with an instantaneous growth mechanism at short experimental time scales (being indeterminate over longer periods), however, this changes to one of a progressive growth mechanism when additives were included in the coating bath. The current efficiency of zinc deposition in the DES without additives was 95%, which was reduced when additives were included. The resultant surface morphologies, thickness, topography, roughness and crystal structure of the Zn coating were revealed by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD), demonstrating that those additives serve as effective brighteners that can produce highly uniform and smooth zinc deposits.

The work herein concentrates on the electrochemical detection of heavy metal ions, specifically cadmium and lead ions. The introduction and modification of functional groups such as Schiff bases had led to an enhanced sensitivity of the electrode to analytes. In this study, a platinum electrode has for the first time been modified with poly(3,4- ethylenedioxythiophene) (PEDOT/Schiff base) in CH2Cl2 containing Bu4NPF6 for use to detection cadmium (II) and lead (II) ions. The structure and morphology of the polymer coatings were characterised by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM), respectively. The electrochemical synthesis and redox state response in monomer-free synthesised films have been studied by cyclic voltammetry. Moreover, the effect of scan rate on the electrochemical behaviour of the modified electrodes was also studied. The voltammetric findings have been used to calculate the surface coverage required for the polymer films and the stability of polymer electrodes in the monomer-free solutions. Square wave voltammetry (SWV) was applied for the determination of cadmium (II) and lead (II) ion concentrations and to assess the effects of pH on aqueous samples. The limits of detection for the modified electrode for cadmium (II) and lead (II) were found to be 0.95 μg L-1 and 1.84 μg L-1, respectively. These findings revealed that modified films can be considered good candidates for application in electrochemical detection devices

Electroactive polymers such as polyaniline and its derivatives have many potential applications, but the nature of the dopants can have an adverse effect on their properties. Polyaniline (PANI), poly(o-methoxyaniline) (POMA) and poly(o-toluidine) (POT) have been synthesised using appropriate organic acid dopants (2-naphthalenesulfonic acid and 1,5-naphthalenedisulfonic acid) via electrochemical and chemical polymerisation methods, where the later was achieved at pH (1–2) in the presence of ammonium persulfate as an oxidant. The effects of the monomers and organic dopants on the physiochemical properties and morphological surface of the polymers were studied by means of Fourier transform infrared spectroscopy, electrical conductivity measurements, thermogravimetric analysis and scanning electron microscopy (SEM). The above films were also synthesised electrochemically whilst varying conditions such as scan rate, scan number and in aqueous solution of organic acids using cyclic voltammetry techniques. Cyclic voltammetry experiments have been employed to analyse the growth behaviour and electrochemical stability of films in the background electrolytes (monomer-free). It was found that PANI salts displayed higher doping levels and conductivity while POMA and POT salts were found to show lower conductivity and doping levels, respectively. Furthermore the electrochemical response of films was different in the stability and this may be because of the methoxy (–OCH3) and methyl (–CH3) groups located at the ortho position of the aromatic ring structure of the monomers (o-methoxyaniline and o-toluidine). The –OCH3 and–CH3 groups have significant steric effects and can reduce to form long chains of polymers and also decrease conductivity. The SEM showed that the morphologies of the prepared conducting polymers were different, which was associated with the nature and size of the dopant and monomer present in the bath solution.

In this work we report the created films of poly derivatives of aniline by using electropolymerization on platinum (Pt) electrode surface in non-aqueous electrolyte (Ethaline). The electropolymerization process of poly (3-amino benzoic acid) was happened in two electrolytes H2SO4 and HClO4 using a chronoamperometry (constant potential) technique for different times (50s, 100s, and 200s). All synthesized conducting polymer films were characterized by using FT-IR. Scanning electron microscopy (SEM) has been applied to study the morphologies of polymer samples. The electrochemical behaviour of prepared conducting films have studied by cyclic voltammetry. The overall findings shown that use a different electrolyte has led to the produce of various polymeric surface films as shown by scanning electron microscopy (SEM). Moreover, the charge consumed during the electropolymerization was calculated with time.

The optical properties of silver nitrates aqueous solution were investigated at different concentrations (1 x10-1, 1 x 10-2, 5 x 10-2 and 1 x 10-3 M). As well thin silver nitrate films of various thickness (210.76, 223.12, 241.56 and287.87 nm) were prepared via pulse laser deposition (PLD) technique using different laser pulses (250, 200, 150, 100 Pulses). Several optical characterizations were studied such as optical absorption properties, optical energy gap, absorption coefficient, extinction coefficient, index of refraction, reflectivity, transmission, optical conductivity and the real and imaginary electrical insulation constant. The results showed that, as one might expect, the absorption increases with increasing concentration of silver nitrate, while the transmission decreases. Furthermore, it has been observed that there is an increase in the absorption coefficient, extinction coefficient and coefficient of refraction as a function of photon energy with increasing the thickness of thin film, while the transmittance decreases with increasing thickness of the film. Also, the linear optical properties were calculated as a function of photon energy and found to increase with increasing thickness of the film. The optical energy gap was calculated for the allowed direct transfer of thin films different thicknesses and was found to decrease with increasing thickness.

This work will show, for the first time, the effect of nicotinic acid (NA) and 2-methylnicotinic acid (MNA)on the synthesis and properties of conducting polyaniline (PANI). The work investigates the effects of sulphuric acid (H2SO4), nicotinic acid (NA), and 2-methylnicotinic acid (MNA) on the synthesis and properties of polyaniline. The results show that the preparation of polyaniline from a sulphuric acid electrolyte is faster than the preparation from nicotinic acid and 2- methylnicotinic acid electrolytes. Moreover, the electrical conductivity and thermal stability of PANI/H2SO4 were greater than PANI/NA and PANI/MNA. All the polymers prepared in this study were identified using FT-IR. Scanning electron microscopy (SEM) was used to examine the morphologies of the PANI samples, from which it was determined that PANI/H2SO4 has a fibrous and open structure with a higher porosity morphology compared to PANI/NA and PANI/MNA. The electrical conductivities of the PANI samples were measured as 1.09 S cm-1, 0.65 S cm-1 and 0.089 S cm-1 for PANI/H2SO4, PANI/NA and PANI/MNA, respectively. The thermal stability of PANI was examined using the Thermogravimetric Analysis (TGA) technique. PANI/H2SO4 was found to degrade between 450-500°C, while PANI/NA and PANI/MNA decomposed at temperatures between 300-400°C.

The generation and accumulation of environmental pollutant of industrial contaminations gave it a big challenge to develop many removal strategies of pollution. Textile dyes as dispersive blue 26 dye affected by several decolorization parameters like as temperature, initial pH and initial concentrations of dye. These variables parameter were studied on ZnO-dye suspension solution in dark and photoreaction conditions. In dark reaction, with using thermodynamic and kinetic parameters such as ΔH°, ΔS°, ΔG° and Ea, the type of adsorption was determined and found as a physical adsorption, exothermic and fast reaction. Moreover, the results demonstrated that the photoreaction process under UV-light-A would elevated the rate of reaction, percentage of decolorization and accelerated the half-time of decolorization reaction in 50 ppm of dye. The photoreaction of decolorization of this dye acts as pseudo first order kinetics with endothermic, less random less, non spontenous and fast reaction.

Physical properties of pure DESs and DESs mixed with different amounts of water were investigated by different techniques, including, rotational viscometer, Quartz Crystal Microbalance (QCM) and conductivity meter. In order to study heterogeneity of those liquids in nature. Analysis of these data showed some characteristics of heterogeneity, the extent of which depends on the number of hydrogen bond donors in the pure DES.

An economic and sensitive method was developed to measure pyridoxine hydrochloride (vitamin B6) in pharmaceutical formation as an ion pair, as depending on the charge transfer reaction with SDS as a surfactant and a suitable analytical reagent (chlorazol black). The parameters that gave optimum reaction conditions, such as the concentrations of chlorozal black, SDS, pH, equilibration temperature, time and effect of salting were studied to obtain a linear calibration curve where the linearity range was found to lie between 1.22 × 10-3to 34 × 10-2mM, and the detection limit (LOD) 2.56 × 10-4mM. The method was applied successfully to determine vitamin B6 concentrations in various pharmaceutical samples.