Adsorption kinetic study: Effect of adsorbent pore size distribution on the rate of Cr (VI) uptake

Idris, Salah Ali Mahgoub; Alotaibi, Khalid M.; Peshkur, Tanya A.; Anderson, Peter; Morris, Michael A.; Gibson, Lorraine T.

doi:10.1016/j.micromeso.2012.08.001

Cited by 85 publications

(46 citation statements)

References 41 publications

(41 reference statements)

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“…However slightly different hysteresis loops were noted for MCM-TDI-PC4 compared with MCM-TDI-C4 and MCM-TDI-C4S. The broader hysteresis loop for MCM-TDI-PC4 suggested that this material contained pores with different shapes and size [37]. Despite having a similar average pore size to MCM-TDI-C4 and MCM-TDI-C4S, MCM-TDI-PC4 differed in a sense that it has a broader pore size distribution.…”

Section: Effect Of Contact Timementioning

confidence: 90%

Comparative Study of Tributyltin Adsorption onto Mesoporous Silica Functionalized with Calix[4]arene, p-tert-Butylcalix[4]arene and p-Sulfonatocalix[4]arene

2014

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Abstract:The adsorption of tributyltin (TBT), onto three mesoporous silica adsorbents functionalized with calix [4]arene, p-tert-butylcalix[4]arene and p-sulfonatocalix [4]arene (MCM-TDI-C4, MCM-TDI-PC4 and MCM-TDI-C4S, respectively) has been compared. Batch adsorption experiments were carried out and the effect of contact time, initial TBT concentration, pH and temperature were studied. The Koble-Corrigan isotherm was the most suitable for data fitting. Based on a Langmuir isotherm model, the maximum adsorption capacities were 12.1212, 16.4204 and 7.5757 mg/g for MCM-TDI-C4, MCM-TDI-PC4 and MCM-TDI-C4S, respectively. The larger uptake and stronger affinity of MCM-TDI-PC4 than MCM-TDI-C4 and MCM-TDI-C4S probably results from van der Waals interactions and the pore size distribution of MCM-TDI-PC4. Gibbs free energies for the three adsorption processes of TBT presented a negative value, reflecting that TBT/surface interactions are thermodynamic favorable and spontaneous. The interaction processes were accompanied by an increase of entropy value for MCM-TDI-C4 and MCM-TDI-C4S (43.7192 and 120.7609 J/mol K, respectively) and a decrease for MCM-TDI-PC4 (−37.4704 J/mol K). It is obviously observed that MCM-TDI-PC4 spontaneously adsorbs TBT driven mainly by enthalpy change, while MCM-TDI-C4 and MCM-TDI-C4S do so driven mainly by entropy changes.

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Section: Effect Of Contact Timementioning

confidence: 90%

Comparative Study of Tributyltin Adsorption onto Mesoporous Silica Functionalized with Calix[4]arene, p-tert-Butylcalix[4]arene and p-Sulfonatocalix[4]arene

2014

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“…The Type H3 hysteresis loop observed that polymers with aggregates of plate-like particles resulting in slit-shaped pores [54]. The NIP1 (Figure 7d) demonstrated a small hysteresis loop compared to the others, indicating a material with well-defined and regular-shaped pores [55].…”

Section: Characterization Of Raft-mips and Mipsmentioning

confidence: 97%

“…The N2 sorption isotherms for MIP2 (Figure 7g) and NIP2 (Figure 7h) indicated a Type-IV isotherms with a hysteresis loops of type H2. It is interpreted that the broad hysteresis loops of type H2 described materials are frequently disordered, with undefined pore size and shape, indicating bottleneck constrictions [55]. Non-closure of hysteresis loops implied incomplete removal of adsorbate from the narrow pores [56].…”

Section: Characterization Of Raft-mips and Mipsmentioning

confidence: 99%

Effects of RAFT Agent on the Selective Approach of Molecularly Imprinted Polymers

2015

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Two types of reversible addition-fragmentation chain transfer molecularly imprinted polymers (RAFT-MIPs) were synthesized using different monomers, which were methacrylic acid functionalized β-cyclodextrin (MAA-β-CD) and 2-hydroxyethyl methacrylate functionalized β-cyclodextrin (HEMA-β-CD), via reversible addition-fragmentation chain transfer (RAFT) polymerization, and were represented as RAFT-MIP(MAA-β-CD) and RAFT-MIP(HEMA-β-CD), respectively. Both RAFT-MIPs were systematically characterized using Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Brunauer-Emmett-Teller (BET), and rebinding experimental study. The results were compared with MIPs synthesized via the traditional radical polymerization (TRP) process, and were represented as MIP(MAA-β-CD) and MIP(HEMA-β-CD). Morphology results show that RAFT-MIP(MAA-β-CD) has a slightly spherical feature with a sponge-like form, while RAFT-MIP(HEMA-β-CD) has a compact surface. BET results show that the surface area of RAFT-MIP(MAA-β-CD) is higher than MIP(MAA-β-CD), while the RAFT-MIP(HEMA-β-CD) surface area is lower than that of MIP(HEMA-β-CD). Rebinding experiments indicate that the RAFT agent increased the binding capacity of RAFT-MIP(MAA-β-CD), but not of RAFT-MIP(HEMA-β-CD), which proves that a RAFT OPEN ACCESSPolymers 2015, 7 485 agent does not always improve the recognition affinity and selective adsorption of MIPs. The usability of a RAFT agent depends on the monomer used to generate potential MIPs.

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“…Idris et al [62] found that the pore-size distribution, rather than the average pore size, affects the retention of NPs at the microscale. However, no research shows how pore-size distribution affects the retention of NPs at a continuum scale.…”

Section: Bulk Density and Porositymentioning

confidence: 99%

Retention of Nanoparticles: From Laboratory Cores to Outcrop Scale

Singh

Javadpour

2017

Geofluids

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Laboratory experiments on small scale core plugs have shown controlled nanoparticles (NPs) retention. The length scale of subsurface media where NPs must be transported is an important factor that should be accounted for in a comprehensive manner when translating laboratory results to field scale. This study investigates the fraction of NPs retained inside porous media as a function of length scale of the media. A two-dimensional numerical model was used to simulate the retention of NPs at multiple scales of porous media, starting from laboratory scale cores to heterogeneous outcrop scales. Retention of NPs is modeled based on the concept of reversible and irreversible retention, by using the laboratory scale determined parameters. Our results show that the fraction of retained NPs increases nonlinearly with the length scale of the homogeneous media. The results also show that if the heterogeneity of the medium is consistent across scales, the fraction of retained NPs would behave just like homogeneous medium. In this study, small change in heterogeneity at two outcrop scales affects the retention of NPs, suggesting that heterogeneity may significantly impact the retention behavior of NPs that may not necessarily follow the behavior predicted from homogeneous cores (or periodically heterogeneous medium).

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Adsorption kinetic study: Effect of adsorbent pore size distribution on the rate of Cr (VI) uptake

Cited by 85 publications

References 41 publications

Comparative Study of Tributyltin Adsorption onto Mesoporous Silica Functionalized with Calix[4]arene, p-tert-Butylcalix[4]arene and p-Sulfonatocalix[4]arene

Comparative Study of Tributyltin Adsorption onto Mesoporous Silica Functionalized with Calix[4]arene, p-tert-Butylcalix[4]arene and p-Sulfonatocalix[4]arene

Effects of RAFT Agent on the Selective Approach of Molecularly Imprinted Polymers

Retention of Nanoparticles: From Laboratory Cores to Outcrop Scale

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