Assessment of combined electro–nanoremediation of molinate contaminated soil

Abstract

Molinate is a pesticide widely used, both in space and time, for weed control in rice paddies. Due to its water solubility and affinity to organic matter, it is a contaminant of concern in ground and surface waters, soils and sediments. Previous works have showed that molinate can be removed from soils through electrokinetic (EK) remediation. In this work, molinate degradation by zero valent iron nanoparticles (nZVI) was tested in soils for the first time. Soil is a highly complex matrix, and pollutant partitioning between soil and water and its degradation rates in different matrices is quite challenging. A system combining nZVI and EK was also set up in order to study the nanoparticles and molinate transport, as well as molinate degradation. Results showed that molinate could be degraded by nZVI in soils, even though the process is more time demanding and degradation percentages are lower than in an aqueous solution. This shows the importance of testing contaminant degradation, not only in aqueous solutions, but also in the soil-sorbed fraction. It was also found that soil type was the most significant factor influencing iron and molinate transport. The main advantage of the simultaneous use of both methods is the molinate degradation instead of its accumulation in the catholyte.

Nanoremediation technologies for sustainable remediation of contaminated environments: Recent advances and challenges

“…One of the critical issues with nZVI is its limited mobility which hampers its efficiency in soil remediation. Techniques like electrokinetic remediation (EK) assist in soil decontamination by application of direct current, which can enhance the mobility and thus performance of nZVI in treating organic contaminants like polychlorinated biphenyls and molinate pesticide (Gomes et al, 2016(Gomes et al, , 2014. Some of the remediative approaches for the treatment of metal contaminants in soil are shown in Table 4.…”

Nanomaterials for sustainable remediation of chemical contaminants in water and soil

“…Molinate was degraded by nZVI in soils at slower rates than in an aqueous system due to the heterogeneous nature of the soil (Gomes et al, 2014). The molinate degradation occurred via the oxidative pathway, which involved oxygen and the formation of hydrogen peroxide and hydroxyl radicals (Gomes et al, 2014). nZVI was employed along with electrokinetic treatment for the degradation of chlorinated ethenes (CEs) in the presence of Dehalococcoides spp.…”

Nanobiotechnology in Agricultural Sector: Overview and Novel Applications

“…Also, zero valent iron nanoparticles, also known as nZVI, have been widely investigated in order to develop novel nanoremediation techniques [28] [53]. These NPs are good electron donors and have shown capacity to remediate or degrade pesticides such as atrazine, lindane, chloroacetanilide, molinate, malathion, chlorpyrifos, dinoseb, organochlorine pesticides and heavy metals like arsenic, lead, mercury and zinc [49] [52]. Nevertheless, there are also concerns because scientists haven't fully investigated the behavior, toxicity and impact on biological systems of the nZVI once they're applied [28] [52].…”