Bentonite-clay for controlled release formulation of chlorpyrifos in soil environment

Dissertant

al-Wahidi, Bayan Mahmud Abd Allah

Thesis advisor

al-Nahhal, Yasir Zaydan

Comitee Members

al-Agha, Muhammad Ramadan
Ashur, Abd al-Rahim Abd Allah

University

Islamic University

Faculty

Faculty of Science

Department

Department of Environmental Science

University Country

Palestine (Gaza Strip)

Degree

Master

Degree Date

2014

English Abstract

-The excessive usage of pesticides in general and insecticides in particular has shown a significant consequences not only on environment but also on human health.

Our of study focuses on one of organophosphorous insecticides; the chlorpyrifos .

In spite of its efficacy as an insecticides chlorpyrifos has created an environmental problems due to residual presence in soil, aquifer and plants also dangerous health consequences such as carcinogenicity and acetylcholine esterase enzyme inhibition.

This study aims to get a controlled released of chlorpyrifos and to minimize of its leaching towards the aquifer.

Column methods accompanied with bioassay was the method of choice.

The process has been run in an isotherm conditions to study the chlorpyrifos adsorption on bentonite clay and organo-clay.

The non a dsorpted concentrations of the chlorpyrifos were determined using HPLC techniques.

The bioassay using mosquito larvae were used.

Also the IR spectroscopy has been run showing which functionality in organic cations might show better binding with chlorpyrifos.

Results have shown the chlorpyrifos was adsorbed with different ratios, since little adsorption has been noticed on bentonite clay while on organo-clay was in higher amounts according to the organic cations compound added to bentonite.

The results have shown the height adsorbed amount of chlorpyrifos was noticed on (Clay- BTBA0.8).

However, the results show that there is directly proportional between adsorption and alkyl functionality in the organic cations compound.

IR spectroscopy was used to confirm the above result through binding with the chlorpyrifos through its alkyl functionality.

Since the (Clay-BTBA0.8) has shown the dramatic decreasing in its wave length 1549 cm-1 to 1471cm-1 as a clear cut evidence of its stronger binding with chlorpyrifos.

The mobility of chlorpyrifos study using columns method revealed that both agricultural soil as well bentonite clay have a significant release to all layers and the lowest concentration has been found in the first layer (0-5cm) while the results revealed that (Clay-BTBA0.8) has shown lowest release of chlorpyrifos and the highest concentration V of chlorpyrifos was found in the first layer (0-5cm) while the layers (6-20cm) didn’t show any release towards them.

The results have revealed that the chlorpyrifos is concentrated at the top soil layer and bentonite clay which indicated that the organic matter in agriculture soil, surface area and high cations exchange capacity (CEC) for bentonite clay as well as the modified surface character of bentonite clay through its conversion from hydrophilic to the corresponding hydrophobic feature.

The bioassay using mosquito larvae has shown dead larvae in all layers of agricultural soil and bentonite clay while in organo-clay lower dead larvae were detected and the most distinguished organo-clay among all types the (Clay-BTBA0.8) that was accompanied with highest ratio of dead larvae in the top soil layer (0-5cm) while in the layers (6-20cm).

For that the bioassay can be considered as good route for detecting the chlorpyrifos in all layers.

Main Subjects

Earth Sciences, Water and Environment

Topics

• Clays
• Environmental aspects

No. of Pages

59

Table of Contents

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-533042