Experimental and Theoretical Analysis of Lead Pb2+ and Cd2+ Retention from a Single Salt Using a Hollow Fiber PES Membrane

Abstract

The present work reports the performance of three types of polyethersulfone (PES) membrane in the removal of highly polluting and toxic lead Pb2+ and cadmium Cd2+ ions from a single salt. This study investigated the effect of operating variables, including pH, types of PES membrane, and feed concentration, on the separation process. The transport parameters and mass transfer coefficient (k) of the membranes were estimated using the combined film theory-solution-diffusion (CFSD), combined film theory-Spiegler-Kedem (CFSK), and combined film theory-finely-porous (CFFP) membrane transport models. Various parameters were used to estimate the enrichment factors, concentration polarization modulus, and Péclet number. The pH values significantly affected the permeation flux of the Pb2+ solution but only had a slight effect on the Cd2+ solution. However, Cd2+ rejection was highly improved by increasing the pH value. The rejection of the PES membranes increased greatly as the heavy metal concentration rose, while the heavy metal concentration moderately affected the permeation flux. The maximum rejection of Pb2+ in a single-salt solution was 99%, 97.5%, and 98% for a feed solution containing 10 mg Pb/L at pH 6, 6.2, and 5.7, for PES1, PES2, and PES3, respectively. The maximum rejection of Cd2+ in single-salt solutions was 78%, 50.2%, and 44% for a feed solution containing 10 mg Cd/L at pH 6.5, 6.2, and 6.5, for PES1, PES2, and PES3, respectively. The analysis of the experimental data using the CFSD, CFSK, and CFFP models showed a good agreement between the theoretical and experimental results. The effective membrane thickness and active skin layer thickness were evaluated using the CFFP model, indicating that the Péclet number is important for determining the mechanism of separation by diffusion.

Performance Evaluation of Polyethersulfone Membranes for Competitive Removal of Cd2+, Co2+, and Pb2+ Ions from Simulated Groundwater

“…Increasing the solubility of metal ions due to the pH change leads to increase the tendency of metals to attach to water molecules and pass through the membrane pores within the permeate. Therefore, the rejection of the single 7 Geofluids metals using the prepared PES fibers was significantly higher the rejection of them when they were incorporated in binary solutions in the current study [35].…”

“…These results can be illustrated as that the efficacy of hollow fiber highly depends on the texture properties of membrane such as the wall thickness of the fiber, porosity, pore size, and pore size distribution at the fiber surface shown in Table 1. The characterization of PES2, PES1, and PES3 discussed previously in [35] showed that PES2 had the lower thickness, wider pore size distribution, larger pore size, and porosity; thus, it gave the higher permeation flux. Figure 2 displays the effect of initial Pb 2+ ion and Cd 2+ ion concentration on the permeate flux for three types of PES membrane used for the separation of binary aqueous The same results were obtained from Figure 4 that presents the effect of initial Cd 2+ ion and Co 2+ ion concentration on the permeate flux of PES1 and PES3 membrane used for the separation of binary aqueous solution at pH 6 ± 0:2 for a time of 30 min.…”

Adopting Sustainable Jatropha Oil Bio-Based Polymer Membranes as Alternatives for Environmental Remediation

“…A filtration experiment was conducted using a customized crossflow filtration system (Figure 1), and the details can be found in our previous work [40]. The concentration of Cu(II) ions was analyzed using atomic adsorption spectroscopy (AAS) and further used in Equation (1) to calculate the observed Cu(II) ions removal [41,42]:…”

“…However, Halim et al (2021) reported that R 2 continued to increase with more added terms, without considering the significance of each model term. Thus, the adjusted-R 2 (adj-R 2 ) and predicted-R 2 (pred-R 2 ) are more reliable in analyzing the model fitting [41]. Both adj-R 2 and pred-R 2 values depend on the significant terms considered in any work [76].…”

“…Upon application of pressure, solutes are suspended near the membrane surface, while water is forced to flow through the semipermeable membrane. In a pressure-driven membrane system, concentration polarization or accumulation of solutes occur as the pressure increases, leading to a decline in the separation efficiency [41,42].…”