Dodecyl benzene sulfonate adsorption isotherm

Experimental isotherm data for the adsorption of four solutes, phenol, p-bromophenol, p-toluene sulfonate, and dodecyl benzene sulfonate onto activated carbon are shown in Figures 1 to 4. The isotherm constants are estimated using a nonlinear parameter estimation program, and are shown in Table 1. The parameter estimation program uses the principal axis method to obtain the parameters, a, b and 3 that will minimize the sum of the squares of the differences between experimental and computed isotherm data. 

Figure 4. Adsorption isotherm for dodecyl benzene sulfonate (O) experimental data, (--------------------------) 3-parameter equation...

As seen from Table 2, phenol, j>-toluene sulfonate and 2 bromophenol have similar adsorption rate characteristics. The equilibrium data for these solutes indicate that phenol and p-toluene sulfonate have similar energies of adsorption (24), as indicated by the constant b in the component isotherm (qe Qbx,ce/ (1 + bLCe) -bromophenol and dodecyl benzene sulfonate are adsorbed more strongly than phenol (22). 

In the study by Bocharov and Krasovskij [305], the concentration Cm for maximum surfactant adsorption at the water/air interface and the maximum permissible concentration (MPC) of surfactants present in household waters are compared and a large table of data given. For example, for sodium alkyl sulfates, the MPC and Cm values, respectively, are 0.5 and 0.6 0.1 for dodecyl benzene sulfonate 0.5 and 0.4 0.1. For nonionics R(OC2H4)OH, where R=aliphatic radical and n = ethoxy groups number, these values are for R=C]o- Ci3/n=7 0.1 and 0.12 0.3 for R=Cio- Ci8/n=10 0.1 and 0.10 0.02. Thus, adsorption isotherm studies are very promising for the determination of MPC in comparison with the frequently applied foaming method where the MPC is determined at a concentration where dynamic foam bubbles appear in the waste water. 

Doping dodecyl benzene sulfonic acid (DBSA) into PANI/carbon nanotube composite can fabricate PANI/carbon nanotube-DBSA nanocomposite [56]. The preparation, as well as the adsorption to Cr(VI), is depicted in Figure 11.11 with the pseudo-second-order kinetics and Freundlich isotherm model with maximum monolayer adsorption capacity of 55.55 mg/g. Electrostatic interactions between PANI and Cr(VI) anions are the predominant driving forces for this adsorption process. 

---

See also in sourсe #XX -- [ ]

---