Aly Derbalah

Removal of Heavy Metals from Aqueous Solution by Zeolite in Competitive Sorption System

In this study, the sorption behaviour of natural (clinoptilolite) zeolites with respect to cadmium (Cd), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) has been studied in order to consider its application to purity metal finishing wastewaters. The batch method has been employed, using competitive sorption system with metal concentrations in solution ranging from 50 to 300 mg/l. The percentage sorption and distribution coefficients (Kd) were determined for the sorption system as a function of metal concentration. In addition lability of the sorbed metals was estimated by DTPA extraction following their sorption. The results showed that Freundlich model described satisfactorily sorption of all metals. Zeolite sorbed around 32, 75, 28, 99, and 59% of the added Cd, Cu, Ni, Pb and Zn metal concentrations respectively. According to the percentage sorption and distribution coefficients values, the selectivity sequence of studied metals by zeolite can be given as Pb> Cu> Zn> Cd> Ni. About 57, 47, 78, 22, and 29% from the total sorbed Cd, Cu, Ni, Pb and Zn recovered by DTPA indicating that lability of the adsorbed Ni was higher than, Cd, Cu, Zn, and Pb respectively. These results show that natural zeolites hold great potential to remove cationic heavy metal species from industrial wastewater.

Photocatalytic removal of fenitrothion in pure and natural waters by photo-Fenton reaction

The photocatalytic removal kinetics of fenitrothion at a concentration of 0.5 mg l−1 in pure and natural waters were investigated in Fe(III)/H2O2/UV–Vis, Fe(III)/UV–Vis and H2O2/UV–Vis oxidation systems, with respect to decreases in fenitrothion concentrations with irradiation time using a solar simulator. Fenitrothion concentrations were determined by HPLC analysis. Furthermore, total mineralization of fenitrothion in these systems was evaluated by monitoring the decreases in DOC concentrations with solar simulator irradiation time by TOC analysis. It was shown that the degradation rate of fenitrothion was much faster in the Fe(III)/H2O2/UV–Vis system than the Fe(III)/UV–Vis and H2O2/UV–Vis systems in both pure and river waters. Consequently, the mineralization rate of fenitrothion was much faster in the Fe(III)/H2O2/UV–Vis system than in the other two systems. The high OH generation rate measured in the Fe …

Antifungal activity of fabricated mesoporous alumina nanoparticles against rot root disease of tomato caused by Fusarium oxysporium

BACKGROUNDThe present work involved the synthesis and characterisation of mesoporous alumina sphere (MAS) nanoparticles to evaluate their biological activity against tomato root rot caused by Fusarium oxysporium, as compared with the recommended fungicide, tolclofos‐methyl, under laboratory and greenhouse conditions. The effects of MAS nanoparticles on the growth of tomato plants were also evaluated and compared with those of tolclofos‐methyl.RESULTSThe physical characteristics and structural features of MAS nanoparticles, such as their large surface‐area‐to‐volume ratio, active surface sites and open channel pores, caused high antifungal efficacy against F. oxysporium. MAS nanoparticles presented an antifungal potential similar to that of tolclofos‐methyl and much greater than that of the control under both laboratory and greenhouse conditions. The highest growth parameters were …

Distribution, seasonal pattern, flux and contamination source of pesticides and nonylphenol residues in Kurose River water, Higashi-Hiroshima, Japan

Agricultural pesticides significantly improve crop yields and pesticides protect against pests. Japan is one of the main users of pesticides worldwide, with more than 450 active products distributed among 5400 commercial products (Japan Plant Protection Association, 2000). On the other hand, pesticides have become universal contaminants found in all segments of the environment and create many hazards to the environment and human health. Pesticide contamination in fresh water, which has emerged as an important environmental problem in the last few decades, is causing concern with respect to long-term and lowdose effects of pesticides on public health as well

Efficacy and safety of some plant extracts against tomato early blight disease caused by Alternaria solcmi

In an attempt to establish new control practices with low mammalian toxicity and low persistence in the environment against plant pathogens plant pathogens Subject Category: Organism Groups

Temporal trends in organophosphorus pesticides use and concentrations in river water in Japan, and risk assessment

We reviewed organophosphorus pesticide use in Japan between 1982 and 2016 using data from the National Institute of Environmental Studies. Organophosphorus pesticide concentrations in river water throughout Japan were taken from the literature, and risk assessments were performed for some organophosphorus pesticides based on risk quotients and hazard quotients. Assessments were performed for 20 common pesticides, including insecticides, fungicides, and herbicides. The amounts used decreased in the order: insecticides > herbicides > fungicides. Organophosphorus insecticide and fungicide use have decreased over the last four decades, but organophosphorus herbicide use has increased. During this period, annual organophosphorus pesticide use was the highest for chlorpyrifos (105,263 tons/year) and the lowest for glyphosate-sodium (8 tons/year). The ecotoxicological risk assessment …

Fabrication and characterization of graphene oxide–titanium dioxide nanocomposite for degradation of some toxic insecticides

Graphene oxide–titanium dioxide (GO@TiO2) nanocomposite with mean diameter size of 14 nm has been fabricated, characterized, and used as photocatalyst for degradation of two highly toxic insecticides, namely carbaryl and imidacloprid. Characterizations of GO@TiO2 have been carried out using various analytical and spectroscopic techniques. Compared to TiO2NPs, the fabricated GO@TiO2 nanocomposite has advantage of its smaller band gap. The finding that the photocatalytic degradation of the examined insecticides by the fabricated GO@TiO2 is more efficient compared to that of TiO2NPs suggests the superiority for using the fabricated GO@TiO2 nanocomposite for degradation of the examined toxic insecticides.

Fate of imidacloprid in soil and plant after application to cotton seeds

This study aimed to investigate the persistence of imidacloprid in soil after application to cotton seeds and to obtain a complete picture on the mass balance of this compound in soil and cotton plants. The study was carried out as a pot culture experiment under laboratory conditions using a Gaucho formulation containing 14C-labeled imidacloprid. Three treatments of cotton seeds were made in sandy loamy soil: live seeds grown in autoclaved soil, dead seeds put in live soil and live seeds grown in live soil. Results showed that total 14C recoveries decreased by time ranging 93.8–96.2, 77.1–88.4 and 53.5–62.4% of the applied radioactivity at 7, 14, and 21 d after application, respectively. The reduction in the extracted 14C from soil coincided with the increase of non-extracted ones. Levels of bound 14C was always less in autoclaved soil than in live ones. Results revealed also that only 1.8–6.8% of the applied 14C …

Some recent approaches to control Tuta absoluta in tomato under greenhouse conditions

Tuta absoluta (Meyrick) is considered the major pest that attacks tomato in many countries. Some insecticides (indoxacarb, imidacloprid) and non-traditional methods (culture filtrate of Bacillus thuringiensis, Artemisia cina extract, clove oil and nanosilica) were evaluated against T. absoluta in tomato under greenhouse conditions. Furthermore, GC-MS analysis was carried out to identify the chemical components of B. thuringiensis culture filtrate as well as A. cina and clove oil extracts. Nanosilica was the most effective treatment against T. absoluta followed by A. cina, imidacloprid + A. cina, indoxacarb, filtrate of B. thuringiensis, imidacloprid, indoxacarb + A. cina and clove oil treatments, respectively. The mixing of the tested insecticides with A. cina improved the efficiency against the tested insect relative to using insecticides alone. The results suggest possible use of the tested natural products and …

Mesoporous Alumina Nanoparticles as Host Tunnel‐like Pores for Removal and Recovery of Insecticides from Environmental Samples

Water contamination with lindane, which is a persistent, toxic, and priority insecticide, is a major problem worldwide. This study presents the fabrication of mesoporous alumina nanoparticles (MA-NPs) with a large surface-area-to-volume ratio, active surface sites, and open channel pores to trap/adsorb insecticide molecules, such as lindane. Key factors, such as temperature, pH (ie, 4.5), adsorbate-adsorbent concentration, and contact time, influence the thermodynamics and kinetics of heterogeneous lindane-MA-NP adsorption. Results show that the maximum adsorption capacity (q^ sub m^) of lindane is 25.54 mgg^ sup-1^ at 20 C. MA-NPs also exhibits a high uptake efficiency (> 80%) of lindane after 20 cycles, which results in effective regeneration and reusability characteristics. MA-NPs were also applied in real environmental samples from tap and lake water sources contaminated with lindane. The results …