Assessment of the use ofMoringa oleiferaseed husks for removal of pesticide diuron from contaminated water

Abstract

Considering the need for new technologies for the removal of pesticides from the aqueous environment, the Moringa oleifera seed husks (h-MO) were investigated for the diuron adsorption from contaminated water at different temperatures and solute concentrations. The biosorbent used in this study was characterized by chemical, structural and textural analyses. The best experimental condition for the biosorption was determined by evaluating the mass of the biosorbent and the pH solution. We found a good adsorption capacity for the herbicide where the maximum adsorption capacity was 14.74 mg/g at pH 5 and 45°C. In addition, the adsorption process of diuron by the h-MO occurred spontaneously, in which, ΔG° values increased as the temperature increased, meaning that the process tends to a more energetically favourable process at higher temperatures. Both Langmuir and Sips isotherm models presented satisfactory adjustment at all temperatures and the pseudo-second-order model presented the best fit for the experimental results. The application of the intra-particle diffusion model showed that the adsorption process started instantaneously through the boundary layer of the adsorbent and that the pore diffusion step was a limiting step in the process. Finally, the capacity of the h-MO was compared with other adsorbents that had been used for diuron removal from contaminated where it was found that the adsorption capacity of the h-MO is much higher than other natural adsorbents.

Acetaminophen adsorption using a low‐cost adsorbent prepared from modified residues of Moringa oleifera Lam. seed husks

“…(B) refers to mod‐MO. Heterogeneous morphological characteristics and porous and fibrous structures can be observed in both images, in agreement with other authors . Larger pore depths were observed after the chemical and thermal treatment, caused by the destruction of fibrous structures.…”

“…The adsorbent at this stage was denoted as mod‐MO. After separation by particle size, the particles between 600 and 500 μm were selected for the subsequent adsorption tests …”

Soybean hulls as a low‐cost biosorbent for removal of methylene blue contaminant

“…It could be observed that the biosorbent presents a porous, fibrous, irregular, and heterogeneous morphology, characteristic of lignocellulosic materials, as previously verified by Alemdar and Sain . These characteristics were considered to be favorable on the adsorption of organic contaminants since it allows the access of the contaminant molecule to the internal cavities and subsequent retention …”

“…23 These characteristics were considered to be favorable on the adsorption of organic contaminants since it allows the access of the contaminant molecule to the internal cavities and subsequent retention. 10,28 As shown in Figure 2a, SBH has a high carbon and oxygen content whereas a low nitrogen (38.18, 21.82, and 0.04 wt%, respectively), a result expected for an organic material. 5 It should be noted that the elements S and Cl, which are contained in the MB molecule, were not found in the spectrum in Figure 2a.…”

“…7 Several studies investigated the removal of dyes from aqueous solution by adsorption, including MB, achieving high adsorption capacities, percentage removal and cost-effectiveness. [8][9][10][11][12] Conventional adsorption processes use activated carbon due to its high pollutant removal. 13 However, the expensive production of this adsorbent limits its application.…”