Comparative study of pH and polyelectrolyte-based composite formation: adsorption behaviour, time duration, and cost-effectiveness

Composites are vital materials renowned for their lightweight strength and versatility, making them suitable for a wide range of applications. Although various methods for composite formation have been explored, a comparative analysis of pH-based (using HCl and NaOH) and polyelectrolyte-based approaches remains scarce. This study addresses this gap by examining the adsorption behaviour, time efficiency, and cost-effectiveness of these two methods. Both polyelectrolytes and acid/base solutions were used to modify the surface charges of the adsorbent and adsorbate. Key findings include the identification of optimal parameters, such as a 60% guest particle loading for uniform adsorption and four polyelectrolyte layers with two washing cycles to stabilise surface charges in the polyelectrolyte-based method. Smaller host particles (1–3 μm) exhibited higher adsorption due to their greater surface area, with spherical particles showing more uniform adsorption than non-spherical particles. The comparative analysis showed that the pH-based method, optimised at pH 4, resulted in homogeneous composite powder formation without contamination. In contrast, the polyelectrolyte-based method faced challenges, including polymer contamination, agglomeration, and longer processing times. The pH-based method was more time-efficient, requiring 42.8% less time (375 min vs. 656 min) and offering potential cost savings of USD 2980 by eliminating the need for costly polymers and centrifugation equipment. Optimal adsorption of Cu/TiO₂ composites occurred at pH 4, ensuring uniform guest particle distribution. The pH-based method was 42.9% faster than the polyelectrolyte method (375 vs. 656 minutes). The pH-based method could save up to USD 2,980, offering a more cost-effective approach.Smaller host particles (1–3 µm) showed higher adsorption due to their greater surface area. The pH-based method outperformed the polyelectrolyte method in adsorption uniformity, with fewer issues like polymer contamination and agglomeration.