“…Figure 3 shows typical FTIR spectra of WCA and WCT, with similar absorption peaks or spectral bands, before and after Pb(II) sorption. The FTIR spectra of the clean samples show band positions (in parentheses for WCT) at 1/ 3276.6 (3291.4) cm -1 , assignable to typical -OH bond stretching vibrations in samples such as cellulose and lignin (Flores-Trujillo et al 2021 ; Taşar et al 2014 ); 2/ 2910.2 (2914.6) and 1236.1 (1249.0) cm -1 which would be related to the symmetric stretching of the C-H bonds typical in lignocellulosic samples (Heraldy et al 2018 ); 3/ 1627.9 (1600.9) cm -1 assignable to the asymmetric stretching of the double bond of C = O carbonyl groups (Barka et al 2013 ); and 4/ 1373.4 (1366.3) cm -1 , assignable to the stretching C-OH and C = O groups of carboxylates (Barka et al 2013 ); 5/ 1026.1 (1026.1) cm -1 , characteristic of C-O-C stretching in polysaccharides (Morosanu et al 2017 ); Fig. 3 Typical FTIR spectra before (black) and after (red) of Pb(II) sorption by WCA (left) and WCT (right).…”
Section: Resultsmentioning
confidence: 99%
“…Inorganic pollutants include metals and their derivatives from the corrosion of metal structures, mining extraction residues, and industrial discharges such as electroplating and battery manufacturing (Negm et al 2018). Heavy metals are especially dangerous due to their toxicity, persistence, and ability to bioaccumulate in the food chain of living beings (Flores-Trujillo et al 2021). This is the case of Pb(II) that when ingested produces severe disorders in the body, particularly in the nervous system and fertility (Lee et al 2019;Lentini et al 2019;Shooto et al 2020).…”
Agro-industrial waste biosorbents of arabica–coffee (WCA) and theobroma–cocoa (WCT) have been characterized and tested to remove Pb(II) from aqueous media. The maximum adsorption capacity of WCA and WCT (qmax = 158.7 and 123.5 mg·g−1, respectively) is comparable or even higher than for several other similar agro-industrial waste biosorbents reported in the literature. Structural and morphological characterization were performed by infrared spectrometry with Fourier transform (FT-IR), scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS), and charge measurements at the zero point charge (pHPZC). Both biosorbents, WCA and WCT, show cracked surfaces with heterogeneous plates which ones include functional adsorption groups such as OH, C = O and C-O-C. Optimal Pb(II) adsorption occurs for a pH between 4 and 5 at [WCA] and [WCT] dose concentrations of 2 g·L−1. We found that the adsorption process follows pseudo-second order kinetics with a rapid growth rate (almost six times larger for WCA than for WCT), basically controlled by the chemisorption process. The regeneration of both biosorbents was carried out in an eluent of 0.1M HNO3 and they can be efficiently reused up to 5 times.
“…Figure 3 shows typical FTIR spectra of WCA and WCT, with similar absorption peaks or spectral bands, before and after Pb(II) sorption. The FTIR spectra of the clean samples show band positions (in parentheses for WCT) at 1/ 3276.6 (3291.4) cm -1 , assignable to typical -OH bond stretching vibrations in samples such as cellulose and lignin (Flores-Trujillo et al 2021 ; Taşar et al 2014 ); 2/ 2910.2 (2914.6) and 1236.1 (1249.0) cm -1 which would be related to the symmetric stretching of the C-H bonds typical in lignocellulosic samples (Heraldy et al 2018 ); 3/ 1627.9 (1600.9) cm -1 assignable to the asymmetric stretching of the double bond of C = O carbonyl groups (Barka et al 2013 ); and 4/ 1373.4 (1366.3) cm -1 , assignable to the stretching C-OH and C = O groups of carboxylates (Barka et al 2013 ); 5/ 1026.1 (1026.1) cm -1 , characteristic of C-O-C stretching in polysaccharides (Morosanu et al 2017 ); Fig. 3 Typical FTIR spectra before (black) and after (red) of Pb(II) sorption by WCA (left) and WCT (right).…”
Section: Resultsmentioning
confidence: 99%
“…Inorganic pollutants include metals and their derivatives from the corrosion of metal structures, mining extraction residues, and industrial discharges such as electroplating and battery manufacturing (Negm et al 2018). Heavy metals are especially dangerous due to their toxicity, persistence, and ability to bioaccumulate in the food chain of living beings (Flores-Trujillo et al 2021). This is the case of Pb(II) that when ingested produces severe disorders in the body, particularly in the nervous system and fertility (Lee et al 2019;Lentini et al 2019;Shooto et al 2020).…”
Agro-industrial waste biosorbents of arabica–coffee (WCA) and theobroma–cocoa (WCT) have been characterized and tested to remove Pb(II) from aqueous media. The maximum adsorption capacity of WCA and WCT (qmax = 158.7 and 123.5 mg·g−1, respectively) is comparable or even higher than for several other similar agro-industrial waste biosorbents reported in the literature. Structural and morphological characterization were performed by infrared spectrometry with Fourier transform (FT-IR), scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS), and charge measurements at the zero point charge (pHPZC). Both biosorbents, WCA and WCT, show cracked surfaces with heterogeneous plates which ones include functional adsorption groups such as OH, C = O and C-O-C. Optimal Pb(II) adsorption occurs for a pH between 4 and 5 at [WCA] and [WCT] dose concentrations of 2 g·L−1. We found that the adsorption process follows pseudo-second order kinetics with a rapid growth rate (almost six times larger for WCA than for WCT), basically controlled by the chemisorption process. The regeneration of both biosorbents was carried out in an eluent of 0.1M HNO3 and they can be efficiently reused up to 5 times.
“…Weber intraparticle diffusion q t ¼ K di t 0:5 þ C K di -intraparticle diffusion rate constant (5) A T (L mg -1 ) -equilibrium binding constant D-R isotherm qe ¼ Q m exp ÀKe 2 K (mole 2 kJ -2 ) -constant related to biosorption energy (10) e (J mol -1 ) -Polayani potential -…”
Section: Biosorption Models Model Equations Parametersmentioning
confidence: 99%
“…For adsorption, activated carbons are commonly employed due to higher specific surface area, higher stability, and removal efficiency [7], but they are expensive [8]. Therefore, current research practices aim at the preparation of lowcost biosorbents from naturally available biomass [9][10][11][12][13][14][15]. For 2,4-D removal, different biosorbents such as cotton plant ash and char [16], activated carbons from lignocellulosic materials of willow, miscanthus, flax, and hemp shives [17], and water hyacinth [18] were proposed.…”
An acid-thermally modified Merremia vitifolia biosorbent (ATMVB) was used for the removal of 2,4-dichlorophenoxyacetic acid (2,4-D) from its aqueous solution. The characteristics of ATMVB were found to be superior to that of the unmodified Merremia vitifolia biosorbent (UMMVB). Batch biosorption experimental data under the optimal treatment conditions for ATMVB best fitted to a pseudofirst-order kinetics model and Langmuir adsorption isotherm with a defined maximum biosorption capacity. The mechanism of biosorption was explained with two intraparticle diffusion models, namely, Weber and Boyd. The biosorption is exothermic as per the thermodynamic studies. The ATMVB can be considered as a potential biosorbent for the removal of 2,4-D from its aqueous solution.
“…Water quality represents one of the major concerns of the twenty-first century, and therefore, surface and deep-water pollution is a topic of high social and scientific interest in both developing and already developed countries. It is well known that water pollution is closely related to various anthropogenic activities (such as mining, dyeing, municipal and industrial solid waste disposal, incineration and/or openly burning waste, and agricultural soil fertilization [1]), unplanned urbanization, and rapid industrialization. Among many inorganic and organic pollutants, heavy metals and dyes receive widespread attention; their presence in wastewater is a major problem since most of them are potentially hazardous to the environment and human health.…”
This study is aimed at extending the soybean hulls’ lifetime by their utilization as an adsorbent for metal ions (Cd2+ and Cu2+) and dyes (Reactive Yellow 39 (RY 39) and Acid Blue 225 (AB 225)). ATR-FTIR spectroscopy, FE-SEM microscopy, and zeta potential measurements were used for adsorbent characterization. The effect of the solution’s pH, peroxidase extraction, adsorbent particle size, contact time, the pollutant’s initial concentration, and temperature on the soybean hulls’ adsorption potential was studied. Before peroxidase extraction, soybean hulls were capable of removing 72% Cd2+, 71% Cu2+ (at a pH of 5.00) or 81% RY 39, and 73% AB 225 (at a pH of 3.00). For further experiments, soybean hulls without peroxidase were used for several reasons: (1) due to their observed higher metal ion removal, (2) in order to reduce the waste disposal cost after the peroxidase (usually used for wastewater decolorization) extraction, and (3) since the soybean hulls without peroxidase possessed significantly lower secondary pollution than those with peroxidase. Cd2+ and Cu2+ removal was slightly increased when the smaller adsorbent fraction (710-1000 μm) was used, while the adsorbent particle size did not have an impact on dye removal. After 30 min of contact time, 92% and 88% of RY 39 and AB 225 were removed, respectively, while after the same contact time, 80% and 69% of Cd2+ and Cu2+ were removed, respectively. Adsorption of all tested pollutants follows a pseudo-second-order reaction through the fast adsorption, intraparticle diffusion, and final equilibrium stage. The maximal adsorption capacities determined by the Langmuir model were 21.10, 20.54, 16.54, and 17.23 mg/g for Cd2+, Cu2+, RY 39, and AB 225, respectively. Calculated thermodynamic parameters suggested that the adsorption of all pollutants is spontaneous and of endothermic character. Moreover, different binary mixtures were prepared, and the competitive adsorptions revealed that the soybean hulls are the most efficient adsorbent for the mixture of AB 225 and Cu2+. The findings of this study contribute to the soybean hulls’ recovery after the peroxidase extraction and bring them into the circular economy concept.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
