Preparation of PVDF-TiO2 Mixed Matrix Membrane for Skim Natural Rubber Latex Treatment

Abstract

Skim latex, a byproduct of the natural rubber latex centrifugation process, is conventionally solidified using a strong acid due to its low rubber content and high stability. It is imperative to stop the practice of treating skim latex with sulfuric acid as it leads to environment degradation. Membrane technology is preferable to conventional separation technology in certain cases due to its superior ability to regulate treatment rate and ensure high product quality. The membrane separation technique can be employed for treating skim latex, resulting in the production of skim serum and skim latex concentrate. This study created mixed matrix membranes (MMMs) with enhanced characteristics and hydrophilicity by incorporating titanium dioxide (TiO2) and a pore-forming agent of poly (vinyl pyrrolidone) (PVP) into hydrophobic poly (vinylidene fluoride) (PVDF). At the beginning of the study, a solution of Bovine serum albumin (BSA) was used to assess the protein rejection ability. This study additionally investigated the impact of varying concentrations of PVDF polymer (16-19 wt.%) and TiO2 (0-2 wt.%) on the characteristics and performance of the membrane. Field emission scanning electron microscopy (FE-SEM) study showed that the PVDF composite membrane with a PVDF concentration of 16 wt% had the thinnest skin layer and the fewest macro-void forms, in comparison to higher PVDF concentrations. The study utilized PVDF and TiO2 at concentrations of 16 wt.% and 1 wt.%, respectively, which were determined to be the optimal amounts. The hydrophilicity of the membrane was enhanced by the inclusion of 1%wt. TiO2, resulting in an improved contact angle of 71�. The findings indicated that membranes made from PVDF/PVP/TiO2 with a reduced concentration of TiO2 nanoparticles had a decreased average pore size, increased number of pores inside the membrane, and enhanced hydrophilicity of the membrane. The results indicate that the PVDF�PVP�TiO2 membrane reached its highest water flux of 97 L/(m2.h), whereas the PVDF�PEG�TiO2 membrane exhibited a rejection rate of BSA above 97%. Finally, this membrane performed skim latex filtration. The concentrated latex's total solid content rose from 6% to approximately 8%. The PVDF�TiO2-PVP membrane demonstrated the highest skim serum flux, measuring 12.72 L/m2h, whereas the PVDF pure membrane displayed a lesser flux of 8.14 L/m2h. Following the use of sodium dodecyl sulphate (SDS) surfactant for membrane cleaning, the membrane remains viable for reuse and exhibits a consistent and steady skim flux. The reduced flow rate seen during skim latex filtration employing membranes can be attributed to the accumulation of skim latex particles and fouling, as indicated by the FE-SEM data. These findings indicate that the PVDF-TiO2-PVP membrane is highly efficient in skim latex filtration and generating skim serum and skim latex concentrate.

Skim latex, a byproduct of the natural rubber latex centrifugation process, is conventionally solidified using a strong acid due to its low rubber content and high stability. It is imperative to stop the practice of treating skim latex with sulfuric acid as it leads to environment degradation. Membrane technology is preferable to conventional separation technology in certain cases due to its superior ability to regulate treatment rate and ensure high product quality. The membrane separation technique can be employed for treating skim latex, resulting in the production of skim serum and skim latex concentrate. This study created mixed matrix membranes (MMMs) with enhanced characteristics and hydrophilicity by incorporating titanium dioxide (TiO2) and a pore-forming agent of poly (vinyl pyrrolidone) (PVP) into hydrophobic poly (vinylidene fluoride) (PVDF). At the beginning of the study, a solution of Bovine serum albumin (BSA) was used to assess the protein rejection ability. This study additionally investigated the impact of varying concentrations of PVDF polymer (16-19 wt.%) and TiO2 (0-2 wt.%) on the characteristics and performance of the membrane. Field emission scanning electron microscopy (FE-SEM) study showed that the PVDF composite membrane with a PVDF concentration of 16 wt% had the thinnest skin layer and the fewest macro-void forms, in comparison to higher PVDF concentrations. The study utilized PVDF and TiO2 at concentrations of 16 wt.% and 1 wt.%, respectively, which were determined to be the optimal amounts. The hydrophilicity of the membrane was enhanced by the inclusion of 1%wt. TiO2, resulting in an improved contact angle of 71�. The findings indicated that membranes made from PVDF/PVP/TiO2 with a reduced concentration of TiO2 nanoparticles had a decreased average pore size, increased number of pores inside the membrane, and enhanced hydrophilicity of the membrane. The results indicate that the PVDF�PVP�TiO2 membrane reached its highest water flux of 97 L/(m2.h), whereas the PVDF�PEG�TiO2 membrane exhibited a rejection rate of BSA above 97%. Finally, this membrane performed skim latex filtration. The concentrated latex's total solid content rose from 6% to approximately 8%. The PVDF�TiO2-PVP membrane demonstrated the highest skim serum flux, measuring 12.72 L/m2h, whereas the PVDF pure membrane displayed a lesser flux of 8.14 L/m2h. Following the use of sodium dodecyl sulphate (SDS) surfactant for membrane cleaning, the membrane remains viable for reuse and exhibits a consistent and steady skim flux. The reduced flow rate seen during skim latex filtration employing membranes can be attributed to the accumulation of skim latex particles and fouling, as indicated by the FE-SEM data. These findings indicate that the PVDF-TiO2-PVP membrane is highly efficient in skim latex filtration and generating skim serum and skim latex concentrate.