Green isolation of cellulosic materials from recycled pulp and paper sludge: a Box-Behnken design optimization

• Published in: Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering Vol. 59; no. 2; pp. 64 - 75
• Main Authors: Suter, Evans K., Rutto, Hilary L., Seodigeng, Tumisang S., Kiambi, Sammy L., Omwoyo, Wesley N.
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 2024; Taylor & Francis Ltd
• Subjects: Biomedical engineering; Biomedical materials; Box-Behnken design; Cellulose; Cellulose - chemistry; cellulose nanocrystals; cellulose yield; Chemical treatment; Consumer products; Crystals; Design optimization; Environmental cleanup; Industrial applications; Nanocrystals; Nanoparticles - chemistry; Nanotechnology; optimization; Pulp; Pulp & paper industry; Pulp wastes; Recycled materials; recycled sludge; Response surface methodology; Sewage; Sludge; Sodium hydroxide; Stability analysis; Sustainable packaging; Synthesis; Temperature; Thermal stability; Water - chemistry; Box-Behnken design; optimization; recycled sludge; cellulose yield; cellulose nanocrystals
• ISSN: 1093-4529; 1532-4117
• DOI: 10.1080/10934529.2024.2331942

Cellulose was isolated from recycled pulp and paper sludge and used to synthesize cellulose nanocrystals. Response surface methodology and Box-Behnken design model were used to predict, improve, and optimize the cellulose isolation process. The optimal conditions were a reaction temperature of 87.5 °C, 180 min with 4% sodium hydroxide. SEM and TEM results revealed that the isolated cellulose had long rod-like structures of different dimensions than CNCs with short rod-like structures. The crystallinity index from XRD significantly increased from 41.33%, 63.7%, and 75.6% for Kimberly mill pulp sludge (KMRPPS), chemically purified cellulose and cellulose nanocrystals, respectively. The TGA/DTG analysis showed that the isolated cellulosic materials possessed higher thermal stability. FTIR analysis suggested that the chemical structures of cellulose and CNCs were modified by chemical treatment. The cellulose surface was highly hydrophilic compared to the CNCs based on the high water holding capacity of 65.31 ± 0.98% and 83.14 ± 1.22%, respectively. The synthesized cellulosic materials portrayed excellent properties for high-end industrial applications like biomedical engineering, advanced materials, nanotechnology, sustainable packaging, personal care products, environmental remediation, additive manufacturing, etc.