In-Situ Formation of Modified Nickel–Zinc-Layered Double Hydroxide Followed by HPLC Determination of Neonicotinoid Insecticide Residues

The photocatalytic degradation of tylosin by a trimetallic ZnCrNi/GO-layered double hydroxide in the conformation of a clustered crumb sheet

Industrial wastewater from drug production is one of the contributors to water pollution. For drug wastewater treatment, photodegradation-based chemical technology has gained more attention because of the drug's microbicidal nature and stability. A zinc-chromium-nickel trimetallic-layered double hydroxide compounding with graphene oxide catalyst (ZnCrNi/GO) was synthesized and exhibited a clustered crumb sheet morphology. The prepared catalyst was characterized by a scanning electron microscope (SEM) equipped with an energy-dispersive X-ray spectrometer (EDS), Fourier transform infrared (FTIR) spectra, and X-ray photoelectron spectroscopy (XPS). The results of material analysis established the crystallographic structures of catalysts and evidenced the successful synthesis. The ZnCrNi/GO nanohybrid revealed a higher activity of approximately 90% degradation of tolysin under high-pressure mercury lamp irradiation. The optimized condition of the catalyst dosage of 500 mg/L and the natural pH of the solution at 7.0 under the tylosin concentration of 10 mg/L with high photocatalytic efficiency was explored. In addition, the main reactive species involved in this photocatalysis degradation were explored as the active cavity h+ and ·O2- to a certain extent by the radical trapping experiments. Reuse experiments have shown that as-prepared catalysts possessed the properties of high efficiency and long-lasting catalytic performance, which could meet pharmaceutical wastewater treatment. A three-metal-layered double hydroxide composed by the metal of Ni, Zn, and Cr was synthesized and attached onto graphene oxide. The catalytic materials obtained in this way have a significant catalysis efficiency to tylosin with the likely degradation mechanism of the active cavity h+ and the oxidative capacity of hydroxyl radials.

Honey contamination from plant protection products approved for cocoa (Theobroma cacao) cultivation: A systematic review of existing research and methods

The main component of chocolate, cocoa (Theobroma cacao), is a significant commercial agricultural plant that directly sustains the livelihoods of an estimated forty to fifty million people. The economies of many cocoa producing nations, particularly those in the developing world, are supported by cocoa export revenue. To ensure satisfactory yields, however, the plant is usually intensely treated with pesticides because it is vulnerable to disease and pest attacks. Even though pesticides help protect the cocoa plant, unintended environmental contamination is also likely. Honey, produced from nectar obtained by honeybees from flowers while foraging, can serve as a good indicator for the level of pesticide residues and environmental pesticide build-up in landscapes. Here, we use a systematic literature review to quantify the extent of research on residues of pesticides used in cocoa cultivation in honey. In 81% of the 104 studies examined for this analysis, 169 distinct compounds were detected. Imidacloprid was the most frequently detected pesticide, making neonicotinoids the most frequently found class of pesticides overall. However, in cocoa producing countries, organophosphates, organochlorines, and pyrethroids were the most frequently detected pesticides. Interestingly, only 19% of studies were carried out in cocoa producing countries. We recommend prioritizing more research in the countries that produce cocoa to help to understand the potential impact of pesticide residues linked with cocoa cultivation in honey and the environment more generally to inform better pesticide usage, human health, and environmental policies.