Spent Coffee Grounds as an Adsorbent for Malathion and Chlorpyrifos—Kinetics, Thermodynamics, and Eco-Neurotoxicity

Abstract

Coffee is one of the most popular beverages, with around 10.5 million tons manufactured annually. The same amount of spent coffee grounds (SCGs) might harm the environment if disposed of carelessly. On the other hand, pesticide contamination in food and biowaste is a rising problem. Because pesticides are hazardous and can cause serious health consequences, it is critical to understand how they interact with food biowaste materials. However, it is also a question if biowaste can be used to remediate rising pesticide residues in the environment. This study investigated the interactions of SCGs with the organophosphate pesticides malathion (MLT) and chlorpyrifos (CHP) and addressed the possibility of using SCGs as adsorbents for the removal of these pesticides from water and fruit extracts. The kinetics of MLT and CHP adsorption on SCGs fits well with the pseudo-first-order kinetic model. The Langmuir isotherm model best describes the adsorption process, giving the maximal adsorption capacity for MLT as 7.16 mg g−1 and 7.00 mg g−1 for CHP. Based on the thermodynamic analysis, it can be deduced that MLT adsorption on SCGs is exothermic, while CHP adsorption is an endothermic process. The adsorption efficiency of MLT and CHP using SCGs in a complicated matrix of fruit extracts remained constant. The neurotoxicity results showed that no more toxic products were formed during adsorption, indicating that SCGs are a safe-to-use adsorbent for pesticide removal in water and fruit extracts.

Preparation of Aminated Sodium Lignosulfonate and Efficient Adsorption of Methyl Blue Dye

“…The diagram in Figure 9 b illustrates the relationship between t 0.5 and q t , displaying the three linear phases of methyl blue as observed in the intra-particle diffusion model. This model encompassed solution diffusion, intra-particle diffusion, and the adsorption of the adsorbent on both internal and external adsorption sites [ 40 , 41 ]. As shown in Table 1 , the k p value exhibited a gradual decrease, indicating a deceleration in the adsorption process.…”

Highly Sustainable Dyes Adsorption in Wastewater Using Textile Filters Fabricated by UV Irradiation

“…The filter adsorption breakpoints for Congo Red are 6 and 18 h. The first rapid step is due to the diffusion of Congo Red through the solution to the surface of the filter, while the second step represents the diffusion of Congo Red into the internal pores of the filter. The third step is the final equilibrium [ 37 ]. The k id value decreases after the first breakpoint, and decreases significantly again after the second breakpoint, indicating that equilibrium is reached and the adsorption rate slows down.…”

Adsorption Properties and Mechanism of Copper Ions from Wastewater by Lessonia nigrescens and Lessonia nigrescens Residue

“…Hence, in this study, kinetic models, including the Pseudo-first model, Pseudo-second order model, Elovich model, and Intraparticle diffusion model, were conducted by fitting the time adsorption curve. The kinetic fitting plots and parameters are concluded in Figures 12 and 13 and Table 3 Important information such as adsorption rate and desorption rate can be obtained from the Elovich model by determining the initial adsorption rate α (mg/g min) and the desorption constant β (g/mg) [58]. According to Figure 12 and Table 3, the initial adsorption rate α was 20.5102 mg/g min, and the desorption constant β was 0.3725 g/mg in this study.…”