Bio-Adsorbent Derived from Sewage Sludge Blended with Waste Coal for Nitrate and Methyl Red Removal: Synthesis, Oxidation, Performance and Environmental Consideration

Low-cost bio-adsorbents were synthesized using two types of sewage sludge: D, which was obtained during the dissolved air flotation stage, and S, which was a mixture of primary and secondary sludge from the digestion and dewatering stages. The sewage sludge was mixed with waste coal before being activated with Potassium Hydroxide (KOH) and oxidized with ammonium persulfate (APS). The nitrate and methyl red removal capacities of the synthesized bio-adsorbents were evaluated and compared to those of industrial activated charcoal. The oxidation surface area of bio-adsorbents derived from sludge S shrank by six fold after modification, while those derived from D only varied narrowly from 312,72 m2/g to 282,22 m2/g, but surface modification had no effect on inorganic composition in either case. The adsorption of nitrate and methyl red (MR) was performed in batch mode, and the removal processes followed the pseudo second order kinetic model and the Langmuir isotherm fairly well. The adsorption capacities of nitrate and MR were higher at pH=2 and pH=4, respectively. The total nitrate Langmuir adsorption potential was DC-5-750 (26,735 mg/g) > commercial activated carbon (Com-AC) (20,61 mg/g) > DC-55-750M1 (17,06 mg/g), and for MR, Com-AC (196,07 mg/g) > DC-5-750M2 (175 mg/g).Statement of Novelty: This paper examines how the chemical structure of activated carbon derived from sewage sludge and blended with waste coal is altered during the chemical activation process to provide the optimal porous surface for nitrate and methyl red adsorptive remediation. The formation of carboxylic sites or the transformation of oxygen sites to carboxylic sites is the aim of the oxidation process of activated carbon in general. Ammonium peroxydisulfate was chosen because of its ability to oxidize the surface without significantly altering the porous structure and increase surface acidity by increasing carboxylic group presence. There are no studies that we are aware of that use ammonium peroxydisulfate to oxidize activated carbon from sewage sludge blended with waste coal

Synthesis and Impedance Spectroscopy of Poly(p-phenylenediamine)/Montmorillonite Composites

Poly(p-phenylenediamine)/montmorillonite (PPDA/MMT) composites were prepared by the oxidative polymerization of monomers intercalated within the MMT gallery, using ammonium peroxydisulfate as an oxidant. The intercalation process was evidenced by X-ray powder diffraction. The FT-IR and Raman spectroscopies revealed that, depending on the initial ratio between monomers and MMT in the polymerization mixture, the polymer or mainly oligomers are created during polymerization. The DC conductivity of composites was found to be higher than the conductivity of pristine polymer, reaching the highest value of 10−6 S cm−1 for the optimal MMT amount used during polymerization. Impedance spectroscopy was performed over wide frequency and temperature ranges to study the charge transport mechanism. The data analyzed in the framework of conductivity formalism suggest different conduction mechanisms for high and low temperature regions.

Synthesis of Metal-Polymer-Semiconductor Diode Using Polyaniline by Chemical Oxidative Method and its Temperature Dependent Electrical Conductivity Behaviour

The interfacial layer of pristine polyaniline (PANI) polymer was prepared using chemical oxidative method with 0.2 M concentration formerly, aniline hydrochloride was oxidized with ammonium peroxydisulfate 0.25 M in aqueous medium at 1-2 ºC next to aniline, stirring time and polymerization temperature are considerable causing parameters of polymerization reaction, harmoniously metal polymer- semiconductor (MPS) constructions of Cu/PANI/n-Si Schottky barrier diodes with different acids (HCl, acetic acid, nitric acid and sulfuric acid) was fabricated. The structural analyses of XRD sizes of the elements revealed that the crystal structure of distortion and converted into amorphous nature and SEM revealed that the morphology of pristine PANI powders. The FT-IR spectra confirmed that ammonium peroxydisulfate with pristine PANI along with band formation. The optical property of PANI was analyzed using UV-vis spectra and deliberate with minimum band gap 3.1 eV by means of HCl. The electrical property I -V temperature ranges 30 to 120 ºC represents that the maximum average conductivity obtains as 0.70 × 10-2 S/cm for 0.2 M HCl. The lowest ideality factor (n) and minimum barrier height (ΦB) values were achieved for HCl of Cu/PANI/n-Si Schottky barrier diode (SBDs) under the explanation disorder.

Submicrometric Fibrillar Structures of Codoped Polyaniline Obtained by Co-oxidation Using the NaClO/Ammonium Peroxydisulfate System: Synthesis and Characterization

A mixture of ammonium peroxydisulfate and sodium hypochlorite (NaClO) (co-oxidating system) were used to obtain polyaniline (PANi) doped with HCl and camphorsulfonic acid (CSA) (co-doping). The effect of HCl/CSA ratio added during polymerization on structure, morphology and electrical conductivity of the conducting polymer was investigated. When NaClO is used, the polymerization rate is substantially increased and the morphology changes from micrometric granular to nanometric fibrillar. CSA was used as complementary dopant but also to improve the solubility of PANi in common solvents. However, results suggest that quinone-like heterocycles containing carbonyl radicals as well as phenazine-type aromatic rings might be impeding an efficient doping in detriment of the conductivity.

Hydrothermal Synthesis of PbO2/RGO Nanocomposite for Electrocatalytic Degradation of Cationic Red X-GRL

PbO2 nanoparticles were prepared using a simple hydrothermal method with β-PbO as precursor and ammonium peroxydisulfate as oxidant. During the hydrothermal condition with ammonium peroxydisulfate, the formed hydroxyl radical has played a key role in the oxidation of β-PbO to PbO2. The size of as-prepared PbO2 nanoparticles was in the range of 25–50 nm. Reduced graphene oxide (RGO) was successfully prepared by the simple reduction reaction of graphene oxide by sodium borohydride and the obtained RGO was then incorporated into the PbO2 nanoparticles. The surface of ITO electrode was modified with the as-prepared PbO2/RGO nanocomposite. The constructed PbO2/RGO/ITO electrode was subsequently applied for the catalytic degradation of cationic red X-GRL which was an azo dye in wastewater. The effects of reaction time, applied current density, and initial concentration of dye on the color removal and COD removal were thoroughly investigated. All results demonstrated that the degradation performance of the electrode modified with PbO2/RGO nanocomposite was extremely excellent.