Investigating the Adsorption Kinetics of Dimethoate, Malathion and Chlorpyrifos on Cellulose-Derived Activated Carbons: Understanding the Influence of Physicochemical Properties

Abstract

In light of the escalating environmental concerns regarding pesticide accumulation, it is imperative to devise efficient strategies for their removal. Among the various options, activated carbons have emerged as promising candidates for adsorptive pesticide removal due to their many advantages, such as large surface area, well-developed porosity, and cost-effectiveness. However, the intricate relationship between the properties of these materials and their performance in pesticide adsorption remains largely unexplored. This study primarily focuses on examining the adsorption kinetics of three organophosphate pesticides: dimethoate, malathion (aliphatic), and chlorpyrifos (aromatic), using a range of cellulose-based activated carbon fibers with diverse specific surface areas, pore size distributions, and elemental compositions. By employing sophisticated data analysis tools, principal component analysis, and semi-empirical quantum chemical calculations, this study uncovers the importance of these distinct properties in efficiently removing structurally diverse pesticides. The results of the adsorption experiments suggested that these processes can be described using a pseudo-second-order kinetic model, which is confirmed via multiple linear regression. The obtained data suggest that the most effective carbon material for pesticide removal should have a pore diameter of approximately 4 nm, low oxygen content, a unimodal pore size distribution, and a high presence of sp2 domains. The insights from this research have the potential to guide the development of improved adsorbents and facilitate the rational selection of adsorbents tailored to specific pollutants based on their physicochemical properties and the pollutants’ chemical structure. By shedding light on the vital connection between adsorbent properties and performance, our findings significantly advance sustainable and effective pesticide removal, thereby fostering a cleaner and healthier environment.

Nitrogen-Doped Carbon Cryogels as Adsorbents: Efficient Removal of Organophosphate Pesticides from Water and Assessment of Toxicity Reduction

“…The highest concentration of sp 2 moieties is observed in the case of the CCN6 samples (Table 4, 56.3% of total observed surface carbon moieties). However, this sample also has an average pore diameter under 4 nm, which could lead to hindered adsorption of CPF on the pore walls [31]. Thus, we believe that in the case of the CCN series of samples, the adsorption performance is determined by a complex interplay between the surface chemistry and texture of the adsorbents.…”

“…First, with the increase in nitrogen content, the polarity of the surface is expected to increase due to the charge redistribution caused by the differences in electronegativities of carbon and nitrogen. On the other hand, there is a change in the pore sizes with nitrogen content increase, and the sample CCN8 has pores above 4 nm, being optimal for chlorpyrifos removal [31], in addition to lower surface oxygen content compared to CCN2 and CCN10 samples, enabling the interactions of aromatic moiety of chlorpyrifos with the surface. Thus, the maximum adsorption of chlorpyrifos by CCN8 is due to sufficiently large and optimal pore sizes, able to accommodate higher amounts of chlorpyrifos compared to samples with larger and smaller pores, and relatively lower surface oxygen content compared to the samples with larger pores and larger pore volumes (CCN2 and CCN10).…”

“…Besides the chemical [21] and microbial degradation of OPs [22][23][24], their adsorption on different types of materials is currently an essential strategy for OP remediation. A multitude of studies can be found within the existing body of literature reporting pesticide adsorption on various materials, like mesoporous monetite [25], porous metal−organic frameworks mineral surfaces [21,[26][27][28][29], organohydrotalcite [30], activated carbon [31][32][33][34][35], zeolites [36][37][38], materials from graphene family [39][40][41][42], and others. When comparing these different classes of adsorbents, it is important to note that the evaluated adsorption performance greatly depends on the experimental conditions.…”