Quantitative structure-activity relationship using molecular connectivity for the activated carbon adsorption of organic chemicals in water

QSAR Models To Predict Effect of Ionic Strength on Sorption of Chlorinated Benzenes and Phenols at Sediment–Water Interface

“…Many semi-theoretical models describing the QSARs have been proposed to predict the sorption parameters including the octanol-water partitioning coefficient, the LSE model, (Nirmalakhandan and Speece, 1993;Luehrs et al, 1996), the MCI model (Blum et al, 1994;Nirmalakhandan and Speece, 1988), and the solvophobic theory (Belfort et al, 1984). While utilising the above QSARs, it is hypothesised that the sorption coefficients normalised to the organic carbon fraction of the sediment (K exp oc ) values for pollutants in fact depend upon the background ionic strength of the system and the validity of this approach has been demonstrated by incorporating the ionic strength term into the three QSARs namely octanol-water partitioning coefficient model (Kow model), the LSE model, and the MCI model.…”

“…Many semi-theoretical quantitative structure activity relationships (QSARs) have been proposed to parameterise sorption onto soils/sediments (Baker et al, 1997;Meylan et al, 1992), sorption onto activated carbon (Blum et al, 1994;Luehrs et al, 1996;Belfort et al, 1984), sorption onto wastewater solids (Dobbs et al, 1989), adsorption of organic vapours onto activated carbon (Urano et al, 1982;Nirmalakhandan and Speece, 1993;Prakash et al, 1994), dissolution of compounds (Kamlet et al, 1986;Lane and Loehrs, 1995;Speece, 1988, 1989;Dunnivent et al, 1992), Henry's law constants (Nirmalakhandan and Speece, 1988;Dunnivent et al, 1992;Nirmalakhandan et al, 1997;Brennan et al, 1998), chemical biotransfer (Dowdy et al, 1996), chemical toxicity (Blum and Speece, 1990;Xu and Nirmalakhandan, 1998); and octanolwater partition coefficients (Sablijic et al, 1993). It is well known that the physico-chemical interactions depend on chemical properties of the pollutant such as aqueous solubilities, octanol/water partition coefficients, or structural characteristics including substituted groups on the pollutant molecule, molar volume of the molecule, topology as well as the intrinsic properties like polarity and polarisability of the pollutant molecules (Westall et al, 1985;Kamlet et al, 1986).…”

“…Lately, more attention has been given to applications of QSARs to predict sorption parameters at the soil or sediment interface (Meylan et al, 1992) because such parameterisation can help in a variety of situations including prediction of local and regional impact of aquatic environment, understanding relative importance of fate (Baker et al, 1997) and transport processes in aquatic systems such as oceans, rivers, aquifers, and lakes, remediation of soils, sediments, and aquifers, bioaccumulation, biomagnification, toxicity to life forms, and bioavailability. Some of the most commonly used QSARs for prediction of sorption capacities at the soil-water interface include the octanol-water partitioning coefficient model (Means et al, 1980;Karickhoff, 1981;Piwomi and Banerjee, 1989;Chiou, 1983;Schwarzenbach et al, 1993), the Linear Solvation Energy model (Nirmalakhandan and Speece, 1993;Luehrs et al, 1996), Molecular Connectivity Indices model (Blum et al, 1994;Nirmalakhandan and Speece, 1988;Xu and Nirmalakhandan, 1998); the Solvophobic Theory (Belfort et al, 1984); and the combination of polarisability parameter, molecular connectivity index, and hydrogen bonding index model (Nirmalakhandan et al, 1997). All these QSARs have essentially tried to focus on several complex physico-chemical surface interactions including adsorption, absorption, ion exchange, pore diffusion, redox reaction, precipitation, dissolution, acid/base hydrolysis, formation of co-ordinated complexes giving rise to the polynuclear species (Weber et al, 1991;Banerji et al, 1993;Gao et al, 1998).…”

Washing of Marine Coastal Sand in a Batch Reactor: Sorption and Desorption of BTEX

“…For example, specific studies have been carried out for washing soils/sediments contaminated with organics 2,4,15 and inorganics 1,8,9,13,16 and also modeling the sorption and desorption phenomenon. 17 Many isolated research efforts on development and application of quantitative structure activity relationships (QSARs) for predicting the sorption and desorption equilibrium at the activated carbon/water interface or activated carbon/air interface [18][19][20][21][22] have been reported in the literature. However, no studies on modeling the soil-washing techniques and incorporating the QSARs for prediction of the thermodynamic limits of sorption and desorption into the soil-washing model have been reported.…”

“…The descriptors are chemical or physical characteristics obtained experimentally or from the structure of the chemical. 21 First, a training set of sorption data is used to statistically establish the mathematical relationship between a sorption property and the descriptors. The QSAR can then be used to predict the sorption properties of untested chemicals for which the descriptors are known.…”