Aniline Concentration Research Articles

The potential application of agroforestry residues in the adsorption of aniline

A low-cost activated carbon based on agroforestry residues (AAC) was synthesized and characterized to remove aniline (AN), a healthy and environmentally toxic substance. The batch adsorption assays were used to assess the effect of contact time (1, 2, 6, 12, and 24 h), pH (2, 4, 6, and 8), and with 1, 5, and 10 mg/L AN concentration. The adsorption mechanism of AN on ACC and commercial carbons (GAP and PAC) was evaluated and compared through Langmuir, Freundlich, and Temkin isotherms. The results show that AN removal increases with decreasing pH, reaching a maximum removal capacity of AAC of 90 %. AAC resulted in similar efficiency to GAC > 90 % to 1 and 5 mg/L. Langmuir shows the best-fit model reaching an R2 of 0.98. These models explain that the adsorption mechanism of AN on ACC is homogeneous, and monolayer adsorption occurs, achieving a maximum capacity of 1.20 and 1.16 mg/g for ACC and PAC, respectively, with a possible endothermic mechanism suggested by Temkin. The results showed that AAC could be considered an effective and economical adsorbent in removing the AN.

An environmentally sustainable ultrasonic-assisted exfoliation approach to graphene and its nanocompositing with polyaniline for supercapacitor applications

In the present work, a green high-yielding method for the preparation of graphene is introduced via ultrasonic-assisted liquid phase exfoliation (LPE) of graphite in a green solvent medium, since the common preparation method of graphene via graphite oxide is hazardous. A high concentration of 3.2 mg/ml graphene is achieved here in a comparatively short duration of 3 h ultrasonication. By using a mixed solvents strategy (acetophenone and isopropyl alcohol, 1:19 V/V), surface energy requirements needed for the exfoliation of graphite are satisfied here with acetophenone, where isopropyl alcohol further facilitated the exfoliation via non-conventional CH-π and OH-π interactions. Turbostratic graphene in high-yield (16 %) in a simple means of ultrasonic assisted LPE is the added attraction of the present procedure. The less-defective structure of graphene, its few-layered turbostratic nature, and edge functionalization of the sheets are evident from the material characterization via Raman spectroscopy, XRD, TEM-SAED, and XPS analyses. Here, we report a combination of the attractive conducting polymer polyaniline (PANI) with the as-prepared graphene for supercapacitor applications, where the PANI/graphene nanocomposites with different aniline concentrations (PANI1.125/G, PANI4.5/G, and PANI9/G) have been prepared via in-situ polymerization of aniline in the graphene dispersion. The structure and morphology of the nanocomposites are investigated using different characterization techniques which revealed that the molecular structure of the PANI is retained in the nanocomposites even with a strong interaction with graphene. FESEM and TEM images revealed the good coverage of graphene sheets with PANI that limit the volume change of PANI during the repeated charge-discharge processes. Electrochemical studies showed that PANI4.5/G has the highest specific capacitance of 126.16 mF/cm2 at a current density of 1 mA/cm2, resulting from the perfect combination of the pseudocapacitance behavior of the PANI along with the electrical double layer capacitance of graphene. A symmetric supercapacitor device is also fabricated with PANI4.5/G, which showed the highest areal capacitance of 116.38 mF/cm2 similar to that with three-electrode studies and also good cycling stability with 87 % capacitance retention in the specific capacitance after 6000 cycles. It also exhibited an energy density of 16 µWh/cm2 (0.29 Wh/kg) and a power density of 3.99 mW/cm2 (72.72 W/kg).

Roles of silica coating on nanosized zero-valent iron in sequential reduction–oxidation process in a system containing persulfate

A sequential reduction–oxidation process using silica-coated nanosized zero-valent iron (nZVI) particles (nZVI@SiO2) and persulfate for mineralizing recalcitrant compounds was developed, and the effects of the process on nitrobenzene were evaluated. This sequential process significantly enhanced contaminant mineralization, which could not be effectively achieved by reduction or oxidation alone. The nZVI@SiO2 rapidly reduced nitrobenzene to aniline, then the aniline concentration gradually decreased after persulfate had been added and initiated sequential oxidative degradation. The SiO2 coating on the nZVI@SiO2 limited outward mass transfer of reaction products and increased the efficiency with which nitrobenzene was converted into aniline. Slow release of Fe(II) caused by the coating caused persulfate activation and subsequent aniline oxidation to be more sustained and efficient than without the coating. The final nitrobenzene–aniline mineralization efficiency was higher for the nZVI@SiO2/persulfate system than the nZVI/persulfate system. The SiO2 coating of the nZVI@SiO2 particles was an excellent protective layer, protecting the particles from undesirable consumption through reactions with groundwater components. nZVI@SiO2 particle transformations during the sequential process were investigated, and the operating conditions were optimized to maximize the recalcitrant compound removal efficiency. The results indicated that nZVI@SiO2 and persulfate could be used to mineralize organic contaminants in groundwater through sequential reduction–oxidation.

Controlled growth of redox-active polymer nanorods on MOF-derived activated nanoporous carbons: 3D reconstruction study and high-performance supercapacitor

Supercapacitors, which a energy storage systems, have been continuously studied because of their high power density and rapid charging-discharging capacity. Supercapacitors can be classified into pseudocapacitors and electric double-layer capacitors (EDLCs). The effective utilization of these two supercapacitor mechanisms is important for achieving high performance. In this study, highly nanoporous metal–organic framework (MOF)-derived carbon underwent chemical activation with potassium hydroxide to produce a high surface area. Subsequently, activated carbon was combined with a polyaniline (PANI) nanoarchitecture to introduce redox-active sites. Activated MOF-derived carbon provides a high specific surface area for EDLCs, and well-controlled PANI nanorods support large amounts of redox-active sites to achieve high capacitance. The aniline (ANI) concentration, growth time, acid, temperature, and ammonium persulfate (APS):ANI molar ratio were controlled to grow PANI nanorods without aggregation. At a scan rate of 5 mV/s, the capacitance of the PANI-ZIF-8-derived carbon composite reached 635.3 F/g, which was superior than that of ZIF-8-derived carbon (143.4 F/g). It also exhibited excellent durability during cycling, demonstrating that it can serve as a high-performance hybrid electrode material composed of carbon and polymer for supercapacitors.

Degradation of Aniline and Antimony in Printing and Dyeing Wastewater by Micro-Oxygenated Hydrolytic Acidification and Their Removal Effects on Chemical Oxygen Demand and Ammonia Nitrogen

The degradation characteristics of aniline and antimony in printing and dyeing wastewater during the micro-oxygenated hydrolytic acidification process and its effect on COD and ammonia nitrogen removal were investigated in this experiment. Firstly, the effects of control factors such as pH, dissolved oxygen (DO), and sludge concentration on COD and ammonia nitrogen removal in the hydrolysis acidification section were optimized. It was recommended that the pH value should be maintained at 6.5; low DO (0–0.5 mg/L) could assist in the conversion of nitrogen for subsequent treatment; the optimum treatment temperature was 25 °C; finally, it was recommended that the sludge concentration should be controlled at 4 mg/L during the operation. Secondly, the effects of aniline and antimony on COD and nitrogen removal were investigated. It was found that when the concentration of aniline was increased from 0.4 mg/L to 5.4 mg/L, the COD concentration in the effluent increased by 96.5%, which indicated that aniline was toxic to anaerobic sludge and obviously inhibited the degradation of COD. When the concentration of antimony was increased from 0.05 mg/L to 2.05 mg/L, the COD removal rate was only 2.9%, which was much lower than that of the water samples with no antimony added. The anaerobic sludge concentration decreased from 5.58 g/L to 3.44 g/L, which indicated that aniline and antimony had a strong inhibitory effect on the activity of anaerobic bacteria and inversely affected COD removal.

Redundancy and resilience of microbial community under aniline stress during wastewater treatment

Aniline is one of the most toxic and widespread organic pollutants. Although biological treatment is cost-effective and generates minimal secondary pollution, microbial communities are significantly affected by high aniline concentrations, which result in low degradation efficiency. However, a comprehensive understanding of the microbial community response to aniline stress is lacking. Here, we performed a cyclic experiment with aniline concentrations (200, 600, 1200, 600, and 200 mg/L) to investigate the ability of microbial communities to recover their performance after exposure to high aniline concentrations. At aniline concentrations up to 600 mg/L, the bioreactor exhibited high aniline removal efficiency (almost 100 %). Comamonas, Zoogloea, and Delftia played crucial roles in removing aniline and microbial beta diversity changed. Additionally, alpha diversity and network complexity decreased with increasing aniline concentration, but these metrics recovered to their original levels when the aniline concentration was returned to 200 mg/L. Homogeneous and heterogeneous selection dominated microbial community assembly. Therefore, according to the observed variations in community structure and the recovery of keystones after aniline stress, microbial community redundancy and resilience are pivotal for ensuring system stability. Overall, this study provides valuable insights into the redundancy and resilience of microbial communities under aniline stress and establishes a scientific basis for managing and evaluating wastewater treatment plants.

Study of nanosilica coated and polyaniline grafted cotton fabric

Valuable biomass product nanosilica obtained from rice husk has been hybridized with polyaniline through grafting and was used as coating material over cotton fabric using 3-aminopropyltriethoxysilane as crosslinking agent. In order to optimize the coating percentages of nanosilica and polyaniline, different weight concentration of both sodium silicate and aniline were used to develop the nanosilica coated and polyaniline grafted cotton fabric. The resulting cotton fabrics were studied for their UV shielding property, thermal and basic fabric properties. Cotton fabric coated with 50% of aniline and 0.75% of silica (S0.75A50C) affords the highest Ultraviolet Protection Factor (UPF) as 46.2. The result shows that the nanosilica coated and polyaniline grafted cotton fabric possess higher UV shielding when compared with that of neat cotton fabric.

Fabrication of Bi0.90Sm0.1Fe0.97Cr0.03O3@PANI core-shell and improvement of its photocatalyst properties

Bi0.90Sm0.1Fe0.97Cr0.03O3@PANI core-shell structures were made by a two-step method, first, bismuth ferrite nanoparticles by hydrothermal method and then, aniline core-shell by co-precipitation method. The bismuth ferrite (BFO) XRD pattern showed no impurities of Sm, Cr, or their compounds in the samples, indicating that Sm+3 and Cr+3 had been replaced in the BFO structure. The XRD pattern of the Bi0.90Sm0.1Fe0.97Cr0.03O3@PANI core-shell shows all peaks of Bi0.90Sm0.1Fe0.97Cr0.03O3 composition with lower intensity, as a result, the Bi0.90Sm0.1Fe0.97Cr0.03O3 composition is phase single. This lower intensity is attributed to the presence of amorphous polyaniline in the core-shell structure. Since there is in the FT-IR spectrum of the Bi0.90Sm0.1Fe0.97Cr0.03O3@PANI core-shell, characteristic peaks of both polyaniline and bismuth ferrite simultaneously so, the FT-IR spectrum of the Bi0.90Sm0.1Fe0.97Cr0.03O3@PANI core-shell is a perovskite structure. The synthesized samples exhibit weak magnetic properties and behave as a paramagnetic material. The absorption capability of core-shell compared to core nanoparticles has increased in the visible region, and this enhancement is attributed to the influence of the presence of polyaniline. All the peaks in the UV–visible absorption spectrum characterize the nano-sized bismuth ferrite and polyaniline in the UV–visible spectrum of the core-shell. The intensity of the photoluminescence spectrum in the doped sample is significantly higher compared to the core-shell sample. This indicates a much faster recombination rate in the doped nanoparticles compared to the core-shell nanocomposite. The doping of the core with Cr and Sm elements, as well as the coating of the core with a polymeric shell, has led to an increase in the degradation rate of the red dye. We also found that shell thickness plays a vital role in dye degradation efficiency and photocatalytic performance. The Bi0.90Sm0.1Fe0.97Cr0.03O3@PANI core-shell exhibits significant photocatalytic activity under visible light. The photocatalytic studies show that the best sample is Bi0.9Sm0.1Fe0.97Cr0.03O3@PANI core-shell with aniline concentration of 0.2 mL and a pH = 2 which was able to destroy 100 % of Congo red dye molecules.

Pervaporation recovery of aniline using the degradable material poly(butylene adipate‐terephthalate): Experiment and molecular simulation

AbstractPervaporation has been considered a promising technique in the recovery of organic matter in low concentrations. Developing new and efficient pervaporation membrane materials remains the main challenge. In this study, the biodegradable poly (butylene adipate‐terephthalate) (PBAT) membrane was used to recover aniline by pervaporation for the first time. The PBAT membrane showed a good pervaporation performance due to its unique affinity with aniline by the surface adsorption energy calculations. When the aniline concentration in the feed solution was 0.4 wt%, the separation factor of the PBAT membrane exceeded 80. Besides, the results showed that the flux rose with the aniline concentration increasing, which was because of the incremental free volume of PBAT membrane. Moreover, the H‐bond length between aniline and PBAT (1.947 Å) was shorter than that between water and PBAT (2.091 Å) according to the density functional theory (DFT) calculations, which could account for the low diffusion coefficient of aniline from the result of molecular dynamics (MD) simulations. In addition, PBAT membranes displayed excellent stability in pervaporation experiments of more than 80 h. It is anticipated that the PBAT membrane may have great potential in pervaporation recovery of valuable chemicals from dilute aqueous solutions.Highlights Biodegradable PBAT membrane was first used to recover aniline by pervaporation. Low diffusion coefficient of aniline was further explained combining MD and DFT. The PBAT membranes exhibited excellent performance for aniline recovery.

Influence of the aniline concentration on the morphology and property of polyaniline nanotubes and their polymerization mechanism

Polyaniline is a kind of polymer material with excellent electrochemical performance, and it stands out among a number of conductive polymer materials owing to its low cost, easy availability of raw materials, and excellent physical and chemical properties. However, the poor processability of polyaniline impedes its broad application. Preparing nanosized structure and introducing big molecular organic acids as dopant are practical strategies to solve this problem. Here using ammonium persulfate as oxidant, sodium dodecyl sulfate as surfactant, and 3,5-dinitrobenzoic acid as doping acid, polyaniline nanotubes were successfully prepared via emulsion polymerization method and characterized by various measurements. The influence of aniline concentration on the morphology and property of the product was explored. The polymerization mechanism of polyaniline nanotubes was discussed in detail based on the analysis of the microscopic morphology. As the concentration of aniline monomer increases, the position of the characteristic absorption peak in the infrared spectrum of the polyaniline main chain remains almost unchanged, but the ratio of benzene to quinone gradually increases. Along with the increasing aniline concentration, the crystallinity of polyaniline gradually decreases from 56.21% to 40.37%. In addition, the optimal conductivity is 2.05×10−2 S/cm when the concentration of aniline monomer is 0.5 mol/L.

Fabrication of a tailor-made conductive polyaniline/ascorbic acid-coated nanofibrous mat as a conductive and antioxidant cell-free cardiac patch

Polyaniline (PANI) was in-situ polymerized on nanofibrous polycaprolactone mats as cell-free antioxidant cardiac patches (CPs), providing electrical conductivity and antioxidant properties. The fabricated CPs took advantage of intrinsic and additive antioxidant properties in the presence of PANI backbone and ascorbic acid as a biocompatible dopant of PANI. The antioxidant nature of CPs may reduce the serious repercussions of oxidative stress, produced during the ischemia-reperfusion (I/R) process following myocardial infarction. The polymerization parameters were considered as aniline (60 mM, 90 mM, and 120 mM), ascorbic acid concentrations ([aniline]:[ascorbic acid] = 3:0, 3:0.5, 3:1, 3:3), and polymerization time (1 h and 3 h). Mainly, the more aniline concentrations and polymerization time, the less sheet resistance was obtained. 1,1 diphenyl-2-picrylhydrazyl (DPPH) assay confirmed the dual antioxidant properties of prepared samples. The advantage of the employed in-situ polymerization was confirmed by the de-doping/re-doping process. Non-desirable groups were excluded based on their electrical conductivity, antioxidant properties, and biocompatibility. The remained groups protected H9c2 cells against oxidative stress and hypoxia conditions. Selected CPs reduced the intracellular reactive oxygen species content and mRNA level of caspase-3 while the Bcl-2 mRNA level was improved. Also, the selected cardiac patch could attenuate the hypertrophic impact of hydrogen peroxide on H9c2 cells. The in vivo results of the skin flap model confirmed the CP potency to attenuate the harmful impact of I/R.

Sintesis polianilin (PANi) dengan metode polimerisasi interfasial sebagai bahan dasar pembuatan sensor gas amonia (NH3)

One of the main components in IoT-based devices is sensors. Polyaniline is a conductive polymer that has great potential to be developed as an active layer for chemical sensors because it has high sensitivity, is easy to synthesize and its electrical conductivity can be adjusted. This study aims to synthesize and characterize polyaniline using the interfacial polymerization method. In this study, polyaniline was synthesized by varying the aniline concentration of 2, 3, and 5 M, then its functional groups were characterized using FTIR and its conductivity and sensitivity were measured with an LCR meter. The result shows that polyaniline is in the form of emeraldine salt which is characterized by the formation of absorption bands at concentrations of 2, 3, and 5 M, respectively, 1,141.86 cm-1, 1,139 cm-1 and 1,139.93 cm-1. The highest conductivity was obtained at a concentration of 2 M, namely 4.9x10-5 and a sensitivity of 82.8% for an ammonia concentration of 100 ppm. So it can be concluded that the polyaniline obtained is a form of semiconducting emeraldine salt.

Mineralization of high concentration of aniline and other organics in wastewater by catalytic ozonation on CaMn2O4

Aniline is a widely used toxic organic which is difficult to be biodegraded. In this work, the aniline solution with high concentration (200–1000 mg/L) was treated by catalytic ozonation over CaMn2O4 prepared by sol-gel method. COD removal ratio in CaMn2O4/O3 system reached 90 % within 120 min, which is much higher than other reported systems. This system also showed good performance for the treatment of real aniline wastewater from dyeing mill. The physicochemical properties of fresh and used CaMn2O4 catalysts were characterized by XRD, FT-IR, SEM, TEM and XPS. The effects of catalyst concentration, aniline concentration, ozone rate of flow and initial pH on mineralization were studied and optimized. Hydroxyl radical (·OH) was the major specie for the mineralization of aniline. Intermediates from mineralization of aniline were analyzed by GC–MS. Calcium ions can obviously improve the performance of manganese oxides for catalytic ozonation.

Controlling the morphology and properties of electrodeposited polyaniline layer on TiO2 nanotubes

Polyaniline (PANI) layers were electrodeposited, as the conductive emeraldine salt phase (PANI (ES)), on the surface of titanium dioxide nanotubes (TiO2 NTs) to evaluate the protective and photo(electro)chemical performance. TiO2 NTs plates were obtained by anodization, in a two-electrode in the undivided cell. The adjustment of the electropolymerization parameters (e.g. aniline concentration, cycles number in cyclic voltammetry, TiO2 cathodic polarization) allowed the control of the PANI (ES) morphology and film thickness, changing the charge recombination dynamics on the PANI (ES)/TiO2 and PANI (ES)/liquid interfaces. It was observed that lower aniline concentrations resulted in the best control of the electropolymerization process, which ensured the deposition of thin films. The TiO2 NTs/PANI (ES) interface was characterized by absorption and vibrational spectroscopies, and scanning electron microscopy. Electronic and photo(electro)chemical properties of the TiO2 NTs/PANI (ES) films were characterized by photoelectrochemical measurements and electrochemical impedance spectroscopy.

Evaluation of haematological, genotoxic, cytotoxic and ATR-FTIR alterations in blood cells of fish Channa punctatus after acute exposure of aniline

Aniline (C6H5NH2) an important intermediate in the organic and fine chemical industry, is ubiquitously used worldwide. It is one of the important building block for manufacturing of 4,4-methylene diphenyl diisocyanate (MDI), accelerators in rubber processing, dyes, tattoo inks, photographic chemicals, antioxidants, corrosion inhibitors, pharmaceuticals and antiseptics. The current study evaluated 96 h LC50 of aniline and based on this, two sublethal concentrations (4.19 mg/l and 8.39 mg/l) were selected for acute exposure studies in freshwater food fish Channa punctatus. Erythrocytes of fish are nucleated hence they play an important role in physiology, immune system, protein signalling and haemostatic condition along with respiration. Blood samples were collected after 24, 48, 72, and 96 h of exposure to study haematological, cytotoxic and genotoxic effects of sublethal concentrations of aniline in C. punctatus. Symbolic elevation in time and dose dependent DNA damage was observed by comet assay as well as micronuclei assay revealing maximum damage after 96 h of exposure. After aniline exposure, scanning electron microscopy and ATR-FTIR studies showed anomalies in structure and alterations in biomolecules of RBCs of aniline exposed group as compared to control group respectively. Semi prep HPLC studies revealed bioaccumulation potential of aniline in higher concentration exposed group.

Remediation of aniline-contaminated aquifer by combining in-well Rhizobium borbori and circulated groundwater electrolysis

Aniline has become a common groundwater contaminant due to its wide use as a raw material in agriculture and pharmaceutical products. The current technologies for in situ remediation of aniline in groundwater are limited by the strains deficient in bacterial species, limited oxygen supply, excessive waste gas load and cost. Accordingly, we conducted a laboratory sand tank experiment to remediate groundwater contaminated with aniline by combining circulated groundwater electrolysis and in-well Rhizobium borbori, which was isolated from activated sludge. The results of the experiment indicated that the optimum concentration of aniline for Rhizobium borbori is about 5 mg/L, beyond which the maximum cell density and the highest specific growth rate decreases as the aniline concentration increases. The optimized duration for immobilizing the Rhizobium borbori into the bioreactor is 4–5 days. Though the Rhizobium borbori was strongly inhibited by the high-concentration of aniline, the immobilized bioreactor in the 350 mg/L aniline solution successfully formed biofilm. The aniline volatilization had limited influence on the observation of bioremediation performance, and the combination of circulated groundwater and in-well Rhizobium borbori supplied a steady dose of oxygen to the bioreactor efficiently degrading the entire region between the injection and extraction well. In addition, a numerical model for the sand tank remediation experiment was used to estimate the yield coefficient of oxygen to be 0.484 g/g, which indicates the presence of ammonia nitrogen as by-products; accordingly, a smaller wellbore size as well a higher circulation flow rate and intensity of current are recommended to improve the water quality. Despite the positive outcomes and potential of the newly developed technology to degrade subsurface aniline, parallel experiments should be conducted to estimate the environmental risk of the by-products and explore the controlling mechanisms of each component in this comprehensive system.

The Effects of Aniline-Promoted Electron Shuttle-Mediated Goethite Reduction by Shewanella oneidensis MR-1 and theDegradation of Aniline

The biological reduction of Fe (III) is common in underground environments. This process not only affects the biogeochemical cycle of iron but also influences the migration and transformation of pollutants. Humic substances are considered effective strategies for improving the migration and transformation of toxic substances and enhancing the bioavailability of Fe (III). In this study, the electron shuttle anthraquinone-2-sulfonate (AQS) significantly promoted the bio-reduction of Fe (III). On this basis, different concentrations of aniline were added. The research results indicate that at an aniline concentration of 3 μM, the production of Fe (II) in the reaction system was 2.51 times higher compared to the microbial reaction group alone. Furthermore, the degradation of aniline was most effective in this group. The increased consumption of sodium lactate suggests that aniline, under the mediation of AQS, promoted the metabolism of Shewanella oneidensis MR-1 cells and facilitated the involvement of more electrons in the reduction process. After the reaction, the solid mineral Fe (II)-O content increased to 41.32%. This study provides insights into the reduction mechanism of Fe (III) in the complex environment of microorganisms, iron minerals, electron shuttles, and pollutants. It aims to offer a theoretical basis for the biodegradation of aromatic hydrocarbon pollutants.

Response surface methodology use in construction of polianiline-coated carbon paste electrode-based biosensor: Modification and characterization.

In this study, the effect of amperometric glucose biosensor construction and using conditions on the current response was investigated in detail applying experimental design. Polyaniline (PANI) was synthesized on the carbon paste electrode (CPE) surface using the cyclic voltammetry technique in sodium oxalate (NaOx ) electrolyte medium, and an amperometric biosensor was constructed by immobilizing glucose oxidase (GOD). Biosensor preparation (aniline, GOD and NaOx concentrations, and scan rate) and operating conditions (pH and applied potential) were optimized by Box-Behnken and optimal designs, respectively, via State Ease Design Expert 7.0.1.1 software. ANOVA analyses showed that among the biosensor preparation parameters, the NaOx concentration has the highest effect on the current measured in the presence of glucose, whereas in the optimization of pH and potential parameters applied in current measurement studies, it has been revealed that pH has a very high effect on the measured current. Several compounds, such as MWCNT, two different ionic liquids and two different organic molecules were added to carbon paste, and, among them, 2-cyanoethylpyrrole (CPy) enhanced the efficacy highly, most probably due to its polymerization in the paste and increasing the electron transfer rate of the CPE. Sucrose- and lactose-sensitive biosensors were also constructed by co-immobilizing GOD with invertase (INV) or β-galactosidase, respectively, onto modified CPE, and sensitivities to their substrates were shown by cyclic voltammetry and impedance analysis. CPy modification caused an increase in the current values, and also Imax /KM values increased approximately 11.8, 7.83, and 2.56 times for glucose-, sucrose-, and lactose-sensitive CPEs, respectively.

Nucleation and growth mechanisms in the electrochemical synthesis of Ag/polyaniline nanocomposites

Nucleation and growth mechanisms in the synthesis of polyaniline nanowires (PANI NWs) and of silver nanoparticles (AgNPs) which are assembly to PANI NWs, are proposed. Aniline polymerization proceeds over a graphite electrode at potentials that go from 0.9 V to 1.15 V (vs Ag/AgCl), using: 0.25, 0.15, or 0.05 M of aniline in HNO3 solution. In the polyaniline nucleation and growth is postulated a diffusional 3D model that involves the dendrites formation and the unidirectional growing step. At lowest aniline concentration, the transients displayed the typical peaked shape, characteristic of a 3D nucleation and diffusion-controlled growth. Silver nanoparticles are synthesized on the polyaniline/graphite substrate. Current-time transients at −0.1 V and −0.2 V (vs Ag/AgCl), displayed a decreasing in the current which is fit to Cotrell modified diffusion-limited aggregation model. Nanowires and nanoparticles morphology observed by SEM corroborated the proposed mechanisms.

Treatment of aniline-containing wastewater by electrochemical oxidation using Ti/RuO2 anode: the influence of process parameters and reaction mechanism.

Aniline detected in many industrial wastewater is a refractive organic pollutant with strong biological toxicity to aquatic organisms and humans. In this research, electrochemical oxidation process with Ti/RuO2 as the anode has been used to degrade aniline-containing wastewater on a laboratory scale. The influence of anode materials, electrolyte, NaCl concentration, current density, and aniline initial concentration on COD removal, ICE, and Ep were studied. The results showed that Cl- addition in the electrolyte is essential to promote aniline degradation efficiency and avoid the anode being passivated. Furthermore, decreasing the current density, increasing Cl- concentration, and initial aniline concentration are beneficial to increase current efficiency and reduce energy consumption. Although the addition of SO42- has a restriction on the active chlorine evolution process, the conductivity increased, which resulted in the reduction of energy consumption. At last, the aniline degradation mechanism in the presence of chloride ions was summed up and proposed based on the literature.