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A thermodynamic and kinetic study of the adsorption process of Zn (II) and Pb (II) ions from aqueous solution on the surface of graphene oxide (GO) to establish the mechanisms of adsorbate–adsorbent interaction on this surface. The effect of pH on the retention capacity was studied and adsorption isotherms were determined from aqueous solution of t...
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Citations
... In water purification, graphene-based materials are widely used to remove various pollutants, including heavy metals, organic compounds, and even bacteria, because of their combination of large surface area, and chemical stability [29]. Currently, graphene-based adsorbents have gained the interest of researchers as promising adsorbents for heavy metal removal from water and wastewater [30,31]. Graphene is a monolayer of carbon atoms that forms a two-dimensional honeycomb lattice structure [32]. ...
... Pacilé et al. (2011) revealed that the creation of GO sheets comprises structured zones in addition to problematic oxygencontaining functional group sections. Also, Guerrero-Fajardo et al. (2020) reported that from these photos, it is clear that monolayers were easily separated from the initial samples. Additionally, there was a significant surface defect that led to irregularities in the plane, indicating that the monolayers' structure was not entirely flat. ...
... According to the preceding discussion, both FT-IR and XRD further demonstrated the GO sheets successful synthesis. According to the FTIR data of (Guerrero-Fajardo et al., 2020), the development of a band near 1695 cm -1 created by vibrations of the -COOH type (C=O in carboxylic acid) is unequivocal indication that graphene oxide, or GO, was successfully synthesized. The band that corresponds to the C-OH group and appears near 1390 cm -1 in addition to 3470 cm -1 attributed to the alcohol OH group type in contrast to the -COOH collects and the OH bunches adsorption on the GO surface is one of the many groups that demonstrated the successful processing of the GO. ...
... According to Lai et al. (2012) and Khan (2017), the strength of the peak at 230 nm in the UV-visible spectrum of graphene oxide declines as layers number rises. However, Guerrero-Fajardo et al. (2020) found that GO had two distinct bands: one at 235 nm, which was brought on by a change in the electrons' π-π* transition inside the C-C aromatic bond of the graphene layers, and the other, a shoulder-like band at 306 nm, which was linked to the π-π* transition and was brought on by the oxygen content. Fernández-Merino et al. (2010), Lee et al. (2010), and (Kigozi et al., 2020) all came to similar conclusions. ...
... Fig. 4b indicates that the pore size distribution of SMS is a bimodal pore size distribution in the 0-10 nm range with a small number of pores in the 40-80 nm range. It is worth mentioning that in comparison to SMS, GO exhibits lower specific surface area [48]. This means SMS outperforms GO for boosting the hydration of cement particles due their higher reactive surface area. ...
This paper examines the influence of novel sugar beetroot-based micro sheets (SMSs) on the hydration of cement.
The SMS material was added to cement pastes in different concentrations and the hydration kinetics of the
cementitious composites were studied via cyclic voltammetry (CV) and electrochemical impedance spectroscopy
(EIS). The effect of SMS on the hydration development of cement, change in the pore size distribution and
microstructural evolution were also quantified. The CV and EIS results revealed that the synergetic effect of the
reactive SMS surface functional groups and tricalcium silicate (C3S) increased the ionic strength of the pore
solution, ion diffusion rate and charge transport properties within the cementitious pastes. The CV and EIS
measurements correlated well with the two main indicators of the cement hydration rate: the degree of hydration
(DOH) and the calcium hydroxide (Ca(OH)2) content. The delineated hydration kinetics suggested that the SMS
sheets accelerate the dissolution of C3S and increase the hydration depth by channelling water from the pore
solution to the unhydrated cement core thereby amplifying the growth of the hydration phases. As a result, the
mechanical properties of the SMS doped cementitious composites were improved. The proposed SMS sheets are a
potential sustainable and renewable biomaterial for improving the performance and reducing the carbon footprint
of cementitious materials.
... Graphene oxide, synthesized by the well-known modified Hummer method using graphite from waste dry cell battery, showed in the batch experiments 98.9% removal of Pb from its 10 mg/L solution at pH 4. The maximum adsorption capacity was calculated to be 55.80 mg/g [42], while Guerrero-Fajardo et al. reported impressive adsorption capacity for Pb(II) of 987.3 mg/g for GO prepared from graphite sheets [44]. An even higher value (1119 mg/g) was reported earlier for GO prepared through the oxidation of graphite using potassium dichromate [49]. ...
Direct determination of lead trace concentration in the presence of relatively complex matrices is often a problem. Thus, its preconcentration and separation are necessary in the analytical procedures. Graphene-based nanomaterials have attracted significant interest as potential adsorbents for Pb(II) preconcentration and removal due to their high specific surface area, exceptional porosities, numerous adsorption sites and functionalization ease. Particularly, incorporation of magnetic particles with graphene adsorbents offers an effective approach to overcome the separation problems after a lead enrichment step. This paper summarizes the developments in the applications of graphene-based adsorbents in conventional solid-phase extraction column packing and its alternative approaches in the past 5 years.
... The most promising of these technologies is Adsorption because of its low cost, high efficiency, adaptable design, and simplicity of operation. Nanomaterials are the adsorbent in most common adsorption systems because of their singular features, features that make them desirable adsorbents for the removal of heavy metals from contaminated industrial wastewater include a high specific surface area, a high number of binding sites for the adsorbates to be adsorbed, a large number of functional groups, and an acceptable pore size [12,13]. According to several studies, the NGO has exceptional adsorption qualities, particularly in liquid-solid systems. ...
The objective of this work is to remove Vanadium V+5 ions from wastewater by batch adsorption utilizing Nano Graphene Oxide (NGO) since Vanadium presents a hazardous concern due to its effect on biological systems; According to the International Agency for Research on Cancer (IARC), vanadium V+5 ions are a potential human carcinogen. In the adsorption process, the effects of temperature (20-50)°C and initial concentration effect (100-800) mg L-1 were investigated. The adsorption isotherms were identified using a simulated aqueous solution of the V+5 ions and a kinetic and thermodynamic sorption analysis. Both the Langmuir and Freundlich isotherm models were used to fit the data. Due to the correlation coefficient (R2) of 0.999, analyses showed that the Adsorption of V+5 ions by NGO followed the Langmuir model. Kinetic models analyzed Intra Particle Diffusion, Pseudo First & Second Order Models revealed that an Intra-Particle Diffusion model was followed. Thermodynamically, The Adsorption processes were exothermic, random, and spontaneous, all shown by the negative values for Enthalpy ∆H, Entropy ∆S, and Gibbs free Energy ∆G.
... As can be seen in Table 7, the ∆H θ values at 298.15 K to 323.15 K for all three adsorption systems are positive, confirming that these adsorption processes are endothermic processes, which is consistent with the increase in the adsorption amount with increasing temperature [69]. In addition, ∆S θ values at 298.15 K to 323.15 K are positive for all adsorption systems, indicating an increase in the disorganization of the solid-liquid contact interface during these adsorption processes [70]; ∆G θ values at 298.15 K to 323.15 K are negative for all adsorption systems studied in this study, confirming that these adsorption processes are thermodynamically spontaneous and feasible [71]. Table 7. Calculation parameters of thermodynamics for the adsorption of Cr(VI) on GOs. ...
Herein, three types of graphene oxides (GOs, GO-M1, GO-M2 and GO-M3) have been successfully prepared from graphite by three different methods and utilized for the removal of Cr(VI) from aqueous solutions. Further, the effects of initial concentration and pH, adsorbent dosage, contact time and temperature on the adsorption performance of GOs were investigated by batch adsorption experiments. Furthermore, the adsorption mechanisms for Cr(VI) adsorption by GOs are mainly the redox reaction and electrostatic attraction, while there are also pore filling, ion exchange and complexation involved in these adsorption processes. The adsorption kinetic and isotherm data indicate that these adsorption processes of GOs on Cr(VI) are dominantly monolayer chemisorption and equilibrium can be reached in 30 min. The saturation adsorption capacities (Qm, 298.15 K) of GO-M1, GO-M2 and GO-M3 for Cr(VI) are estimated to be 3.5412 mg×g−1, 2.3631 mg×g−1 and 7.0358 mg g−1, respectively. Moreover, the adsorption thermodynamic study showed that these adsorption processes of Cr(VI) by the three types of GOs at 298.15 K to 323.15 K are endothermic, entropy-driven and thermodynamically spontaneous and feasible. Overall, these findings provided vital insights into the mechanism and application of Cr(VI) removal by GOs.
... Adsorption is the most promising of these technologies because of its low cost, high efficiency, versatile design, and ease of operation. Nanomaterials are the adsorbent in the majority of typical adsorption systems because of their unique properties like a specific surface area is high, a large number of binding sites for the adsorbates to be adsorbed, numerous functional groups, and appropriate pore size, This makes them appealing adsorbents for the treating industrial wastewater polluted with heavy metals [12,13]. ...
... Equation (12) can be written in the following equation (13) form, When the system is closer to an equilibrium state, ≫ ( ) -1 : ...
The study's objective is to produce Nano Graphene Oxide (GO) before using it for batch adsorption to remove heavy metals (Cadmium Cd+2, Nickel Ni+2, and Vanadium V+5) ions from industrial wastewater. The temperature effect (20-50) °C and initial concentration effect (100-800) mg L-1 on the adsorption process were studied. A simulation aqueous solution of the ions was used to identify the adsorption isotherms, and after the experimental data was collected, the sorption process was studied kinetically and thermodynamically. The Langmuir, Freundlich, and Temkin isotherm models were used to fit the data. The results showed that Cd, Ni, and V ions on the GO adsorbing surface matched the Langmuir model with correlation coefficients (R2) of 0.999. Kinetic models studied showed that a pseudo-second-order model was followed and thermodynamically, the process was exothermic due to ∆H negative, the reduction in randomness because of negative ∆S. additionally, spontaneous adsorption of metal ions was ∆G negative values influenced.
... The total pore volume of GO (0.0927 cm 3 /g) found from waste dry cells is in good agreement with the GO prepared from commercially available graphite powder. 53,55 It can be concluded that the use of graphite rods of dry cells is also a potential candidate instead of commercially available graphite powder. ...
Graphene oxide (GO) was prepared from the graphite electrode of waste dry cells, and the application of the prepared GO as a potential adsorbent for rapid and effective removal of an antibiotic, azithromycin (AZM), has been investigated. The synthesis process of GO is very simple, cost-effective, and eco-friendly. As-prepared GO is characterized by field-emission scanning electron microscopy, energy-dispersive X-ray, transmission electron microscopy, X-ray diffractometry, Fourier transform infrared spectroscopy, elemental analysis, Brunauer-Emmett-Teller sorptometry, and zeta potential analysis. The obtained GO has been employed for removal of the widely used AZM antibiotic from an aqueous solution. The quantitative analysis of AZM before and after adsorption has been carried out by liquid chromatography tandem mass spectrometry. The adsorption of AZM by GO was performed in a batch of experiments where the effects of adsorbent (GO) dose, solution pH, temperature, and contact time were investigated. Under optimum conditions (pH = 7.0, contact time = 15 min, and adsorbent dose = 0.25 g/L), 98.8% AZM was removed from the aqueous solution. The rapid and effective removal of AZM was significantly controlled by the electrostatic attractions and hydrogen bonding on the surface of GO. Adsorption isotherms of AZM onto GO were fitted well with the Freundlich isotherm model, while the kinetic data were fitted perfectly with the pseudo-second order. Therefore, the simple, cost-effective, and eco-friendly synthesis of GO from waste material could be applicable to fabricate an effective and promising low-cost adsorbent for removal of AZM from aqueous media.
... Because they share an electron pair, GO has a high adsorption affinity for Pb(II) and forms a metal complex with it. Furthermore, Gibbs free energy indicates that Pb(II) adsorption on GO adsorbent is thermodynamical and spontaneous (Guerrero-Fajardo et al., 2020). Cu(II) and Pb(II) sorption employing tragacanth-GO by 0.1 N HNO 3 for 8 h were described by Sahraei et al. (Sahraei et al., 2017). ...
Carbon-centric adsorbents (CCA) are diverse forms, from simple biochar (BC) to graphene derivatives, carbon nanotubes (CNTs), and activated carbon (AC), which have been vastly explored for their removal of a plethora of pollutants, including heavy metals (HM). The prominent features of CCA are their operational attributes like extensive surface area, the occurrence of flexible surface functional groups, etc. This work offers a comprehensive examination of contemporary research on CCA for their superior metal removal aptitude and performances in simulated solutions and wastewater flows; via portraying the recent research advances as an outlook on the appliances of CACs for heavy metal adsorption for removal via distinct forms like AC, BC, Graphene oxide (GO), and CNTs. The bibliometric analysis tool was employed to highlight the number of documents, country-wise contribution, and co-occurrence mapping based on the Scopus database. The coverage of research works in this review is limited to the last 5 years (2017-2021) to highlight recent progress and prospects in using CCAs such as AC, BC, GO, and CNTs to remove HM from aqueous media, which makes the review unique. Besides an overview of the common mechanisms of CACs, the future scope of CAC, especially towards HM mitigation, is also discussed in this review. This review endorses that further efforts should be commenced to enhance the repertory of CCAs that effectively eliminate multiple targeted metals in both simulated and real wastewater.
... Pb ions in an aqueous solution form different hydroxides depending on the pH of the solution [81], which is represented in Eq. (4). ...
Lead (Pb) is a concerning water pollutant worldwide as it is highly toxic to living organisms. In this research, adsorption studies were carried out for the removal of Pb from water. Graphene oxide (GO) was used as adsorbent, which was synthesized by modified hummers method using graphite from waste dry cell battery. The prepared GO was characterized by FESEM, TEM, XRD, BET, Raman, FTIR, and Elemental analysis which revealed that the highly porous GO was successfully prepared from graphite rod of waste dry cell battery. Batch experiments were performed to investigate the effects of pH, contact time, adsorbent dose on the adsorption process, and optimum condition for adsorption was determined. Experiments showed 98.87% removal of Pb (10 ppm) in a very short time (20 min) at pH 4 while adsorbent dose was 0.25 gL⁻¹. The oxygenated groups on the surface of GO played a crucial role in the adsorption of Pb on GO. Experimental data were tested against kinetic and adsorption isotherm models. The adsorption process followed pseudo-second-order kinetics, Langmuir isotherm at lower temperature (20 and 30 °C), and Freundlich isotherm at higher temperature (40 °C). The maximum adsorption capacity was calculated to be 55.80, 54.03, and 51.83 mg g⁻¹ at 20, 30, and 40 °C, respectively. Thermodynamic studies suggested the adsorption was exothermic and spontaneous under 20–40 °C, which indicates that adsorption was feasible. Therefore, this study represents a rapid and efficient method in reducing water contamination caused by Pb.
