Isotherm and kinetic investigations on the adsorption of organophosphorus pesticides on graphene oxide based silica coated magnetic nanoparticles functionalized with 2-phenylethylamine

Functionalized Graphene-Based Materials as Innovative Adsorbents of Organic Pollutants: A Concise Overview

“…Organic covalent functionalization reactions of graphene include two general routes: (a) the formation of covalent bonds between free radicals or dienophiles and C═C bonds of pristine graphene and (b) the formation of covalent bonds between organic functional groups and the oxygen groups of GO (Georgakilas et al, 2012). Characteristic of these processes are the presence of carbonyl, hydroxyl and carboxyl groups (resulting from the oxidation of graphite itself by the Hummers method); nevertheless, functional moieties, such as amines (Wanjeri et al, 2018;Bueno et al, 2017), amides (Ahmed and Kim, 2017;Mrlík et al, 2016), nitro (Begum et al, 2017), thio-compounds (Mahmoodi et al, 2017;Cai and Larese-Casanova, 2016), carbene cycloaddition (Zan, 2014), among others, can be chemically added to the carbon plane edges and surface. Within the covalent routes, a functionalizing group, such as thionyl, can replace the hydroxyl groups that form on the graphene surface after oxidation (Cai and Larese-Casanova, 2016).…”

“…Several works reported in the literature, which have explored the use of graphene based nanomaterials as adsorbent of water pollutants, have highlighted that functionalization increased their adsorption efficiency in comparison to their predecessors Shi and Ye, 2015). Another remarkable characteristic of functionalized graphenes in comparison to GO is their elevated recyclability, which allows their reuse even after more than ten adsorption-desorption cycles (Wanjeri et al, 2018;Nodeh et al, 2015) as summarized in Table 1. However, the functionalization route must be carefully chosen according to the newdeveloped adsorbent and adsorbate properties, as well as the operating conditions of the adsorptive process.…”

“…Pesticides are widely used in agriculture, livestock and pest control; moreover, they have also been used by ordinary people in household gardening and veterinary practice. Many pesticides have aromatic rings in their structure, which leads to carcinogenic diseases, neurotoxicity and other pathologies (Wanjeri et al, 2018). Moreover, organophosphorus pesticide toxicity lies in the fact that these substances are inhibitors of the enzymes acetylcholinesterase, which leads to nervous system malfunction (Lazarevic-Pasti et al, 2018;Heidari and Razmi, 2012).…”

“…This lack of information leads to the assumption that interactions of different natures are involved in the adsorption mechanism. Wanjeri et al (2018) used the polymeric magnetic functionalized GO (2-PEA-Fe 3 O 4 -GO) to remove three types of chlorinated pesticides, Chlorpyrifos, Parathion and Malathion. Excellent adsorption capacity was obtained for Parathion adsorption (135.00 mg•g -1 ); all experiments were conducted at pH 10 and environmental temperature.…”

“…Modified graphene has also been tested as gatekeepers for several chiral molecules, many of them with bioactive and toxic properties (Hauser et al, 2014). Among the advantages of employing functionalization processes on graphene and graphene oxide nanosheets, it can be cited: increase of sorbent selectivity towards specific classes of pollutants (Lazarevic-Pasti et al, 2018;Shrivas et al, 2017); outstanding adsorption performance in terms of capacity and high recoverability (Suo et al 2018;Nodeh et al, 2015;Zhao and Liu, 2014); unlimited possibilities of functionalization, oftentimes by using the same reactant (Wanjeri et al, 2018;Bueno et al, 2017); some non-covalent functionalization can be reversed by non-aggressive methods (McCoy et al 2015); functionalization routes can be developed by using bio and ecofriendly compounds, such as amino acids, wood extracts, chitosan, etc. (Cobos et al, 2018;Xue et al, 2018;Wang et al, 2017b;Wang et al, 2016b).…”