Removal of atrazine and four organophosphorus pesticides from environmental waters by diatomaceous earth–remediation method

Abstract

A new viable remediation technique based on the use of diatomaceous earth is proposed to improve the ecological system. Its ability to remove atrazine and the four organophosphorus pesticides parathion-methyl, chlorpyriphos, fenamiphos and methidathion from river and waste waters has been proven. A series of experiments including variable conditions, such as temperature, pH, contact time, pesticide concentration and adsorbent quantity, were performed to demonstrate the efficiency of pesticide removal from three different water samples. The batch experiments showed that diatomaceous earth was able to remove 95% of chlorpyriphos, 75% of methidathion and parathion-methyl and 55% of atrazine and fenamiphos from all types of waters tested. The individual adsorption of each pesticide on diatomaceous earth could be described by the Freundlich isotherm and a tentative adsorption mechanism was proposed. The Freundlich coefficient (Kf) and Freundlich constant (1/n) appeared to be closely related to the physicochemical properties (Kow, solubility) of the compounds. The actual results support the conclusion that diatomaceous earth has the potential to serve as an extractant in remediation techniques.

Characterization and adsorption properties of diatomaceous earth modified by hydrofluoric acid etching

“…Due to its specific properties (porous structure, high silica content, low density, low conductivity coefficient, etc.) [1,2], DE has extensively been applied in many ways, such as filter aid [3], adsorbent [4][5][6][7][8][9][10], insulating material [11], catalyst support or carrier [12], and natural insecticide or grain protectant [13], etc. It is noted that diatomite only has weak adsorption capacity but excellent absorption power because of its macroporous structure.…”

Silica adsorbent prepared from spent diatomaceous earth and its application to removal of dye from aqueous solution

“…Due to its specific properties (high silica content, high porosity, low density, low conductivity coefficient, etc. ), DE has been applied as a filter aid, adsorbent, filler (packing material), insulator, catalyst (support), anticaking agent, natural insecticide, and grain protectant [2][3][4]. Among them, it is mainly used as a filter aid for applications to difficult-to-filter solids to improve permeability of the filter cake, and where high clarity is required, as in the polish filtration of wine (beer) before bottling and in the production of fruit juices and industrial chemicals (e.g., lubricating oil).…”

Organic xenobiotics removal in constructed wetlands, with emphasis on the importance of the support matrix

“…Diatomite has been tested as an adsorbent for several types of organics, namely dyes [250][251][252][253][254], pesticides [255], phenolic compounds [256] and other aromatics [257].…”