Sustainable Production of Cellulose Nanocrystals with Sulfuric Acid Recycling Using Diffusion Dialysis and Electrodialysis

Abstract

Cellulose nanocrystals (CNCs) are renewable and multifunctional plant-based nanoparticles that are industrially produced by controlled sulfuric acid hydrolysis, resulting in a large amount of acid−sugar mixture, which has potential to be recovered and concentrated for reuse. However, the removal of sugar from the acid−sugar mixture, which was produced by cellulose biomass hydrolysis, is essential before acid recycling. In this study, the acid−sugar mixture was separated from the CNC hydrolysate, and then, a combination process of diffusion dialysis (DD) using anion-exchange membranes and electrodialysis (ED) was used to remove the sugar from the acid−sugar mixture. The operation parameters were optimized and Fenton oxidation (FO) was applied to degrade sugar with a decrease in the chemical oxygen demand (COD Cr ) in the wastewater. As a result, 98.8% sulfuric acid was totally recovered in a practical process, with 92.2% recovery by diffusion dialysis and 87.1% by electrodialysis, and more than 90% sugar was rejected. COD Cr in the wastewater decreased to <500 mg/L by FO treatment. Furthermore, CNCs prepared with the recovered sulfuric acid showed a crystallinity, surface charge, and morphology similar to that prepared with fresh acid. Therefore, this combination process of DD and ED is a green and economic feasible way for acid recycling for sustainable CNC production.

Design of Cellulose Nanocrystal-Based Self-Healing Nanocomposite Hydrogels and Application in Motion Sensing and Sweat Detection

“…According to the existing literature, CNCs were extracted by hydrolysis of microcrystalline cellulose with sulfuric acid, − and PDA coatings were obtained by self-polymerization of dopamine under alkaline conditions at pH = 7.5, while gold nanoparticles (AuNPs) were prepared by utilizing the reducing properties of DA and cocoated with PDA on the surface of CNCs. , CNCs@PDA-Au was prepared by ultrasonication of 3.0 mg of CNCs, 3.0 mg of dopamine hydrochloride, 10.0 mL of Tris–HCl solution (0.005 M), 5.0 mL of water, and 1.0 mL of HAuCl 4 (0.01 M) solution at a constant temperature of 25.0 °C for 3 h. The prepared CNCs@PDA-Au was centrifuged with ultrapure water at 10 000 rpm for 15 min and washed three times.…”

Side Chain Crosslinked Anion Exchange Membrane for Acid Concentration by Electrodialysis

“…Specifically, diffusion dialysis (DD) and electrodialysis (ED) technologies are used for effective separation and recovery of acid components in acidic waste liquid. DD is effective for treating high-concentration waste acid, while ED offers advantages in treating low-concentration waste acid from an economic perspective. − ED utilizes ion exchange membrane’s selective permeability to separate anions and cations, concentrate and desalinate substances . However, the issue of acid leakage poses a challenge in ED technology .…”

Reusable Floating Spherical Hydrogel Evaporator for Solar Desalination with Salt Mitigation and Contaminant Elimination

“…The scarcity of fresh drinking water is a pervasive global problem affecting people worldwide. , Desalination is considered as an effective, sustainable approach to generate fresh water from seawater and brackish water. , Current desalination technologies are based on reverse osmosis, multistage flash distillation, and electrodialysis, which are expensive. − Solar-induced desalination treatment is a cost-effective as well as eco-friendly approach that uses an interfacial evaporation system to isolate the evaporation interface from bulk water. Heat localization is conducted at the air–water interface to avoid the conduction of heat to the entire water mass and achieve efficient evaporation. ,, The use of various photothermal materials having high light absorption and light-to-heat conversion efficiency concentrates heat on the evaporation surface, which accelerates water transport that balances the evaporation rate. − …”