Evaluation of vermicompost as a raw natural adsorbent for adsorption of pesticide methylparathion

Abstract

The assessment of vermicompost (VC) as a low-cost and alternative adsorbent for the removal of the pesticide methylparathion (MP) from an aqueous medium has been investigated by batch and column experiments. Parameters related to MP adsorption, i.e. equilibrium time (61.5 min) and adsorption pH (6.8) were optimized by using Doehlert design. The initial and final MP concentrations after adsorption assays were determined by square-wave adsorptive cathodic stripping voltammetry using an electrode composed of a multiwalled carbon nanotube dispersed in mineral oil. Batch adsorption experimental data were fitted to the Langmuir and Freundlich isotherm adsorptions, and a very good fit to the Langmuir linear model, giving a maximum adsorption capacity (MAC) of 0.17 mg g(-1). This result was very similar to that obtained with the column experiments. In order to evaluate the MP desorption from column packed VC, 100.0 ml of nitric acid solution (pH 3.0) has been percolated through material. No leaching of MP was observed, thus confirming the strong interaction between MP and VC. The satisfactory MAC obtained and low cost makes the VC a reliable natural material for the removal of MP from aqueous effluents.

An Overview of the Environmental Applicability of Vermicompost: From Wastewater Treatment to the Development of Sensitive Analytical Methods

“…However, the great number of electrical charges in vermicompost does not ensure exclusive reversible retention, because cations of transition metals (with free energy levels) tend to form covalent bonds with diverse chemical groups [ 43 ]. As already discussed by Mendes et al [ 37 ], adsorption with some irreversibility was verified for a neutral organic compound (methylparathion).…”

“…The adsorption capacity of vermicompost for organic chemicals was also investigated by Mendes et al [ 37 ], who evaluated the retention of a pesticide (methylparathion). Under controlled experimental conditions of pH (6.8) and agitation time (61.5 minutes), an excellent maximum adsorptive capacity of 170 mg kg −1 was achieved under conditions of irreversibility, which was confirmed by elution tests with an HNO 3 solution at pH 3.0.…”

Vermicomposting: A sustainable tool for environmental equilibria

“…Because of the dyes’ large spatial pores, a greater amount of adsorption occurred than is typically the case with natural dyes. Vermicompost also removed the pesticide methyl parathion, with control conditions for maximum adsorption from the water of pH 6.8 and agitation time of 61.5 minutes (Mendes et al., ). Thus, in elution, methyl parathion was not detected because of the many charged groups present at the surface of the vermicompost due to coulomb forces.…”

Vermicompost as a Potential Adsorbent for the Adsorption of Methylene Blue Dye From Aqueous Solutions

“…They also determined that the performance of vermicompost was better and mainly the functional groups such as aliphatic alcohols, aromatic acids, carbonates, and phosphates contributed to the efficient removal of the metals (9). Pesticide methylparathion removal from water stream via adsorption onto vermicompost was studied as well and the results suggested that experimental data fitted to the Langmuir linear model yielding 0.17 mg/g of maximum adsorption capacity (10).…”