Search

Recently, the development of visible-light-responsive catalysts for the photodegradation of organic pollutants has captured the attention of researchers globally. The ineffectiveness and high costs associated with conventional methods and techniques used for the abatement of water pollution have forced researchers to develop effective and low-cost innovative techniques for this purpose. Photocatalysis is considered an effective protocol for this purpose. Therefore, this study was conducted for the development of the Bi2O3-NiO heterojunction as a visible-light-responsive photocatalyst for the degradation of methyl orange. Ni(NO3)2∙6H2O (Fluka) and Bi(NO3)3∙5H2O (Merck) were used as precursor materials for the synthesis of NiO-Bi2O3. After fabrication, the Bi2O3-NiO heterojunction was characterized using XRD, EDX, SEM, FTIR, and TGA techniques. Then, it was employed as a catalyst for the photodegradation of methyl orange under sunlight irradiation. The fabricated Bi2O3-NiO showed higher photocatalytic activity than Bi2O3 and NiO with 100, 67, and 46% degradation of methyl orange, respectively. The rate constant determined by the non-linear method of analysis for the photodegradation of MO in the presence of Bi2O3-NiO was 3.2-fold and 1.7-fold of the rate constant with NiO and Bi2O3, respectively. The higher photocatalytic activity of Bi2O3-NiO than of its individual components in the present study is also attributed to the separation and transfer of positive holes and electrons. The recycling of spent Bi2O3-NiO under similar experimental conditions exhibited the same photocatalytic activity suggesting the stability of the fabricated Bi2O3-NiO photocatalyst. [ABSTRACT FROM AUTHOR]

A molecularly imprinting polymer (MIP) was synthesized for Basic Blue 3 dye and applied to wastewater for the adsorption of a target template. The MIPs were synthesized by bulk polymerization using methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA). Basic Blue 3 dye (BB-3), 2,2′-azobisisobutyronitrile (AIBN) and methanol were used as a functional monomer, cross linker, template, initiator and porogenic solvent, respectively, while non-imprinting polymers (NIP) were synthesized by the same procedure but without template molecules. The contact time was 25 min for the adsorption of BB-3 dye from 10 mL of spiked solution using 25 mg polymer. The adsorption of dye (BB-3) on the MIP followed the pseudo-second order kinetic (k2 = 0.0079 mg·g−1·min−1), and it was according to the Langmuir isotherm, with maximum adsorption capacities of 78.13, 85.4 and 99.0 mg·g−1 of the MIP at 283 K, 298 K and 313 K, respectively and 7 mg·g−1 for the NIP. The negative values of ΔG° indicate that the removal of dye by the molecularly imprinting polymer and non-imprinting polymer is spontaneous, and the positive values of ΔH° and ΔS° indicate that the process is endothermic and occurred with the increase of randomness. The selectivity of the MIP for BB-3 dye was investigated in the presence of structurally similar as well as different dyes, but the MIP showed higher selectivity than the NIP. The imprinted polymer showed 96% rebinding capacity at 313 K towards the template, and the calculated imprinted factor and Kd value were 10.73 and 2.62, respectively. In this work, the MIP showed a greater potential of selectivity for the template from wastewater relative to the closely similar compounds. [ABSTRACT FROM AUTHOR]