Adsorption of Cd(II) and Pb(II) ions from aqueous solutions using mesoporous activated carbon adsorbent: Equilibrium, kinetics and characterisation studies

In this study, cadmium and lead ions removal from aqueous solutions using a commercial activated carbon adsorbent (CGAC) were investigated under batch conditions. The adsorbent was observed to have a coarse surface with crevices, high resistance to attrition, high surface area and pore volume with bimodal pore size distribution which indicates that the material was mesoporous. Sorption kinetics for Cd(II) and Pb(II) ions proceeded through a two-stage kinetic profile-initial quick uptake occurring within 30 min followed by a gradual removal of the two metal ions until 180 min with optimum uptake (qe,exp) of 17.23 mg g1 and 16.84 mg g1 for Cd(II) and Pb(II) ions respectively. Modelling of sorption kinetics indicates that the pseudo first order (PFO) model described the sorption of Pb(II) ion better than Cd(II), while the reverse was observed with respect to the pseudo second order (PSO) model. Intraparticle diffusion modelling showed that intraparticle diffusion may not be the only mechanism that influenced the rate of ions uptake. Isotherm modelling was carried out and the results indicated that the Langmuir and Freundlich models described the uptake of Pb(II) ion better than Cd(II) ion. A comparison of the two models indicated that the Langmuir isotherm is the better isotherm for the description of Cd(II) and Pb(II) ions sorption by the adsorbent. The maximum loading capacity (qmax) obtained from the Langmuir isotherm was 27.3 mg g1 and 20.3 mg g1 for Cd(II) and Pb(II) ions respectively

Numerical simulation and geological modelling of conceptual fluvial reservoir systems.

The development of a fluvial reservoir oil or gas field poses complex challenges in field development strategies during appraisal and exploration stage due to some subsurface uncertainties. In this study, the channel geometries such as straight-channel, Y-shaped channel and U-shaped channel are assessed based on conceptual geological modelling. In order to provide robust information, a case scenario for both oil and gas fluvial producing reservoir are simulated using ECLIPSE 100-a black oil simulator, with data which has been adopted from Walsh and Gringarten [2]; Hogg et al. [6]. The result of the study shows that the pressure behaviour in the different channels is because of the change in channel geometry. This property determines the hydrocarbon recovery method and as such integration of analytical method, numerical simulation and geological modelling are employed as tools for planning field development strategies in fluvial reservoirs