Photocatalytic oxidation of pollutants in gas-phase via Ag3PO4-based semiconductor photocatalysts: Recent progress, new trends, and future perspectives

Air pollution has become a significant challenge for both developing and developed nations. due to its close association with numerous fatal diseases such as cancer, respiratory, heart attack, and brain stroke. Over recent years, heterogeneous semiconductor photocatalysis has emerged as an effective approach to air remediation due to the ease of scale-up, ready application in the field, use of solar light and ready availability of a number of different effective photocatalysts. To date, most work in this area has been conducted using UV-absorbing photocatalysts, such as TiO2 and ZnO; However, recent studies have revealed Ag3PO4 as an attractive, visible-light-absorbing alternative, with a bandgap of 2.43 eV. In particular, this material has been shown to be an excellent photocatalyst for the removal of many types of pollutants in the gas phase. However, the widespread application of Ag3PO4 is restricted due to its tendency to undergo photoanodic corrosion and the poor reducing power of its photogenerated conductance band electrons, which are unable to reduce O2 to superoxide •O2−. These limitations are critically evaluated in this review. In addition, recent studies on the modification of Ag3PO4 via combination with the conventional heterojunctions or Z-scheme junctions, as well as the photocatalytic mechanistic pathways for enhanced gas-pollutants removal, are summarized and discussed. Finally, an overview is given on the future developments that are required in order to overcome these challenges and so stimulate further research into this promising field

Effect of the temperature on the synthesis of dicalcium phosphate dihydrate

The use of calcium phosphates as biomaterials was largely developed during the last decades. Among the phosphorous compounds solid minerals of biological interest, the dicalcium phosphate dihydrate, (DCPD or brushite) (CaHPO$_{4}$, 2H$_{2}$O), disserves a special attention. It can be prepared in different ways. The manufacture of inorganic phosphate, it is usually produced by the acidulation of limestone form of calcium with phosphoric acid. The synthesis of this phosphate depends on many operational parameters. This study was performed in order to verify the influence of temperature and the time on the chemical purity and the yield of precipitation. All the samples were characterized by X-ray diffraction, infrared spectrometry and chemical analysis

Single and multi-component adsorption of aromatic acids using an eco-friendly polyaniline-based biocomposite

The polyaniline coated with an agricultural waste (Argan nut shell) was prepared via in-situ chemical polymerization and used as an adsorbent material for removal of trimellitic (Tri), hemimellitic (Hemi) and pyromellitic (Pyro) acids from water in single and multi-component systems. The obtained results indicate that the adsorption process was strongly influenced by experimental parameters. The greatest adsorption efficiency was obtained at pH 6, adsorbent dose = 0.5 g/L, T = 25 °C, contact time = 90 min and initial concentration of 20 mg/L. The experimental data for single component systems fitted very well to pseudo-second-order kinetic model (R2 = 0.999). The intraparticle diffusion model suggests that the adsorption of Tri, Hemi and Pyro acids takes place in two successive stages representing the progressive adsorption and equilibrium. The single component adsorption equilibrium data were successfully described by the Langmuir isotherm model (R2 ≥ 0.995). The maximum monolayer adsorption capacity of polyaniline/Argan-nut-shell composite was found to be 209.64, 143.68 and 267.38 mg/g for Tri, Hemi and Pyro acids, respectively. In binary and ternary systems, the competitive behavior of the adsorption process was successfully predicted by an extended Langmuir isotherm model, with interaction parameters obtained from measured single data. Furthermore, the values of thermodynamic parameters (ΔH° ˃ 0, ΔS° ˃ 0 and ΔG ˂ 0) indicate that the adsorption processes were spontaneous, endothermic and physisorption in nature.Scopu

Removal of Cu2+ from Aqueous Solutions by Adsorption on Chemically Modified Cellulosic Supports

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