Enhanced photocatalytic–biological degradation of 2,4 dichlorophenoxyacetic acid

Abstract

2,4-Dichlorophenoxyacetic acid (2,4-D) is the third most commonly used herbicide all over the world. There is a contradicted opinion about its toxicity and its half life in the environment. In this study the most effective method of its degradation and bioremediation has been studied. Two microbial consortia capable of utilizing 2,4-D as a sole source of carbon were isolated from the Egyptian environment. One of the microbial consortia interestingly contained a certain kind of protozoa as one of the mixed consortia members. Degradation of 2,4-D by the microbial consortia was affected by 2,4-D initial concentration, agitation, pH of the medium and temperature. The two consortia were able to degrade up to 700 mg l À1 of 2,4-D. Pre-treatment with UV radiations in the presence of photocatalyst such as TiO 2 accelerates the biodegradation process. The toxic non biodegradable concentration of 2,4-D which was found to be the 800 mg l À1 , was degraded by pre-treatment with UV/TiO 2 and a subsequent microbial inoculation. The combined treatment proved to be an efficient mean of biodegradation and detoxification of toxic non biodegradable concentrations of 2,4-D.ª 2015 Production and hosting by Elsevier B.V. on behalf

Halophiles: biology, adaptation, and their role in decontamination of hypersaline environments

“…Over the past decade, a variety of thermophilic (Rye et al 2009), psychrophilic (Drienovska et al 2012;Novak et al 2013), and non-extremophilic microbes capable of degrading 2,4-D (Fulthorpe et al 1995;González et al 2012;Kumar et al 2014;Samir et al 2015) have been isolated from contaminated marine environments (Chiba et al 2009;Fulthorpe et al 1995;González et al 2012;Kumar et al 2014;Novak et al 2014;Samir et al 2015). However, studies on bioremediation of chlorinated compounds under hypersaline environments are sparse.…”

Fotobi̇yokatali̇z Yöntemi̇ Kullanilarak Pesti̇si̇t Gi̇deri̇mi̇-Derleme Çalişmasi

“…Samir vd. [72] çalışmasında, 2,4-D herbisitinin parçalanması ve biyolojik arıtımı incelenmişlerdir. Mikrobiyal topluluk tarafından 2,4-D parçalanması 2,4-D başlangıç konsantrasyonundan, karıştırma hızından, ortam pH'ı ve sıcaklığından etkilenmiştir.…”

Radiation collector systems comparison in Contaminants of Emerging Concern degradation by solar heterogeneous photocatalysis

“…Advanced Oxidation Processes (AOP) are defined as effective methods for the removal of a large number of persistent contaminants. These make changes in the chemical structure of pollutants until they reach mineralization, transforming organic matter into carbon dioxide and water (Samir 2015). One of the most AOP used is the Heterogeneous Photocatalysis (HP) in wich a semiconductor is irradiated to generate reactive spicies and the greatest used in photocatalytic applications is TiO2, particularly the P-25 (Evonik®), because it presented a higher photocatalytic activity, is not toxic, is stable in aqueous solutions and It is not expensive (Bendjama 2018).…”