Poly(acrylonitrile)/cellulose block copolymer (PAN-b-cell) was prepared by using a free radical initiating process and then the nitrile functional groups of the PAN blocks of the copolymers were transformed into amidoxime ligands. The resulting poly(amidoxime) ligands could complex with heavy metal ions; for example, the reflectance spectra of the [Cu-ligand] n+ was found to be at the highest absorbance, about 94%, at pH 6. The pH was the key parameter for metal ions sensing by the ligand. The adsorption capacity for copper was very good, 272 mg g −1 , with a fast adsorption rate (t1/2 = 10 min). The adsorption capacities for other heavy metal ions such as Fe 3+ , Cr 3+ , Co 3+ and Ni 2+ were also good, being 242, 219, 201 and 195 mg g −1 , respectively, at pH 6. The heavy metal ions removal efficiency from water was 98% at low concentration. The data proved that the heavy metal ions adsorption onto the polymer ligands were well fitted with the Langmuir isotherm model (R 2 >0.99), which suggests that the cellulose-based adsorbent surface namely the poly(amidoxime) ligand, was homogenous and a monolayer. The reusability was examined by a sorption/desorption process for six cycles and the extraction efficiency was determined. This new adsorbent could be reused for 6 cycles without any significant loss in its original removal function.
Chitosan, a versatile natural polymer is an amino polysaccharide prepared by processing shrimp shell waste which involved deacetylation of chitin. To obtain high degree of deacetylation (DDA), several parameters should be performed during alkaline treatment. The present study was undertaken at different time of soaking treatment (once and twice) and temperature (60 o C and 80 o C) to optimize the deacetylation process to produce chitosan with high solubility and degree of deacetylation. It was observed that the highest solubility and degree of deacetylation were obtained when deacetylation process was repeated twice and temperature of 80 o C, with 99.48% and 97.63%, respectively. It can be concluded that by repeating the deacetylation twice with the support of heating treatment, a better quality of chitosan with higher solubility and degree of deacetylation can be produced.
The focus of this study was to compare the yield and characteristics of chitosan produced from different sequences of treatment for deproteination, demineralization and deacetylation. In Process 1, deproteination occurred in the first step followed by demineralization and deacetylation. While Process 2 was started with demineralization step and followed by deproteination and deacetylation. The results show that the percentage yield of chitosan was slightly higher when Process 2 was adopted with 22.22 %. However, the process produced chitosan with lower degree of deacetylation and solubility with high ash content, which were 76.47 %, 37.79 % and 2.67 %, respectively. While, when Process 1 was carried out, the degree of deacetylation of chitosan, solubility and ash content were improved to 91.26 %, 100 % and 0.38 %, respectively, with lower yield of 19.01 %. Therefore, this study suggests the extraction process should be performed by carrying out deproteination step before demineralization and deacetylation (Process 1) to produce a good quality of chitosan.
Composting and anaerobic digestion have emerged as better options for managing food waste and sewage sludge at the campus level. This review highlights the characteristics of food waste and sewage sludge from various global higher education institutions. The composting and anaerobic digestion processes of food waste and sewage sludge will be reviewed and evaluated. Also, the adoption of composting and anaerobic digestion at various campus levels has been reviewed. The challenges and future direction, focusing on managing university campus composting and anaerobic digestion, are discussed as well. This review paper will significantly contribute to the understanding of the potential for managing and handling campus waste in a natural-friendly manner.
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