Utilization of cocoa shell waste cellulose as an additive in cellulose acetate membranes: Impact on membrane properties and performance for salt rejection

Abstract

This study investigates the use of cellulose extracted from cocoa shell waste as an additive in cellulose acetate (CA)-based membranes to enhance membrane properties while minimizing extraction-related waste. Both organic and inorganic extraction solvents were evaluated to determine their impact on porosity, hydrophilicity, mechanical strength, and salt rejection efficiency. Characterization techniques, including Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), contact angle measurements, porosity assessments, and tensile strength testing, were employed. The results showed that the functional groups of the CA membrane remained unchanged with cellulose addition. Membranes containing cellulose extracted with citric acid exhibited higher porosity (500–650 nm) compared to unmodified membranes (300–400 nm) and improved hydrophilicity, with contact angles of 59°–63°. Salt rejection varied with extraction solvents, with hydrochloric acid-extracted cellulose achieving 11.13% rejection and 232.73 L·m⁻²·h⁻¹ flux, while citric acid-extracted cellulose resulted in 8% rejection and 140 L·m⁻²·h⁻¹ flux. Additionally, citric acid-treated membranes demonstrated superior tensile strength. These findings suggest that cocoa shell-derived cellulose can enhance CA-based membranes, contributing to sustainable membrane technology and supporting green processing and circular economy initiatives.