Narrow Results

Organic pollutants in water have been threatening public and environmental health. Developing efficient and sustainable photocatalysts working for degradation of organic pollutants under visible light becomes a big challenge. In this paper, high-efficiency visible light driven catalyst ordered mesoporous graphite nitride carbon (mpg-C₃N₄) was prepared by using SBA-15 as template and dicyandiamide (C₂H₄N₄) as precursor. The specific surface area of mpg-C₃N₄ can be increased remarkably as compared to that of the bulk graphite nitrite carbon (g-C₃N₄) by adjusting the ratio of SBA-15 to dicyandiamide. Photocatalytic performance of mpg-C₃N₄ were evaluated systematically by degradation of Rhodamine B (RhB), malachite green (MG) and tetracycline hydrochloride (TC) under visible light irradiation. The results showed that the mpg-C₃N₄ (1:0.5) has the highest photocatalytic activity and stability and the degradation rate is for RhB, MG and TC are all more than seven times that of bulk g-C₃N₄. After five recycling runs, the mpg-C₃N₄ (1:0.5) remains high photocatalytic activities for the degradation of MG (94%) and TC (81%), respectively. Additionally, radical trapping experiments certified that the main active species are $•{\mathrm{\text{O}}}_2^{-}$ and h${}^{+}$, while the role of $•$OH is irrelevant in the reaction processes. This work provides a promising pathway to prepare metal-free photocatalyst for degradation of organic pollutants under visible light irradiation.

The adsorption of malachite green from an aqueous solution of magnetic Fe₃O₄ was studied in view of the adsorption isotherm, kinetics and regeneration of the sorbent. The adsorption isotherm of MG on nano-Fe₃O₄ composite followed the Langmuir isotherm. Adsorption kinetics was determined from the experimental data. The nano-Fe₃O₄ can be recycled for reuse after regeneration through acetonitrile. The high adsorption capacity and excellent reusability made Fe₃O₄ attractive for the removal of MG from aqueous solution.

The present investigation aims to lighten a quick electrochemical detection technique of malachite green (MG) content using an easy and affordable carbon paste electrode (CPE). MG finds a wide area of application for controlling external fungi plus parasites on the fish egg for its antifungal and antiparasitic features. However, MG is noticed to be dreadfully poisonous and unsafe. Hence, the determination of MG in aquaculture is very much necessary. In this current report, the electrochemical behavior of CPE has been studied using a three-electrode system containing a silver-silver chloride (Ag/AgCl) reference electrode and a platinum counter electrode to record the corresponding cyclic voltammetry (CV) and differential pulse voltammetry (DPV) responses. CV plots in the applied potential range from 0.3 V to 1.5 V described a strong indication of MG existence, while DPV results successfully illustrated the quantification of several MG concentrations. The linear range of operation was from 10$\mu$M to 1000$\mu$M with the lowest limit of detection (LOD) as 0.78 $\mu$M. Various concentrations like 50, 300, 600, 800, and 1000$\mu$M were assessed via principal component analysis (PCA) with effective data clustering (separability index (SI) found as 131.08). The prediction estimations of MG content using PLSR (partial least square regression) along with PCR (principal component regression) algorithms were also carried out, resulting in 95.39% and 93.02% prediction accuracies, respectively. Moreover, applying this CPE over natural aqueous sample extracts exhibited a reasonable recovery rate of 94.85–97.3%.