Environmental Chemistry Letters
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2020
·Vol. 18
·期 4
·1379-1388
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IF 5.922
Zhang Hao,Yang Fan,Lu Chuan,Du Chang,Bai Ruixi,Zeng Xian,Zhao Zhigang,Cai Chunqing,Li Jianguo
Treatment and recycling of radioactive waste are major challenges for the nuclear energy sector. Pertechnetate anions, 99 TcO 4 − , occur in nuclear waste and are formed mainly during nuclear fission. 99 TcO 4 − is a very hazardous contaminant due to its long half-life and high solubility and mobility in water. The effective capture of 99 Tc contamination at legacy nuclear sites remains a serious and unsolved environmental issue. In this work, 99 TcO 4 − /ReO 4 − was adsorbed by compressible graphene–chitosan sponges with grafted tertiary amine groups. Moreover, the hydrophobic branched chains strongly reduced the interference of competitive anions during adsorption. Results show that 99 TcO 4 − /ReO 4 − can be effectively removed even under highly acidic conditions and in the presence of competing anions. More than 98% of 99 TcO 4 − /ReO 4 − was removed using simulated nuclear wastes.
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JOURNAL OF HAZARDOUS MATERIALS
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2020
·
IF 9.038
Wei Ding,Xiaoyan Pang,Zhiwen Ding,Daniel C.W. Tsang,Zhicheng Jiang,Bi Shi
Tanning leather using green biomass-derived polyaldehyde (BPA) is a promising approach to eliminate the widespread Cr pollution in leather industry, but unsatisfactory thermal stability and mechanical strength of the correlated resultant leather limited its industrial application. Herein, we report a green methodology to strengthen BPA tanned leather via introducing chitosan derivatives to crosslink with free aldehyde groups on dialdehyde carboxymethylcellulose (DCMC) tanned leather. H 2 O 2 was employed for purposely modifying chitosan to prepare low-molecular chitosan (LMC) with lower positive charge. The interactions between chitosan/LMC and DCMC were investigated to elucidate the strengthening mechanism. Owing to the weakened hydrogen bonding network and higher accessibility of amino groups on LMC, LMC could react much easier with aldehyde groups on DCMC. Moreover, LMC could efficiently penetrate into the internal fiber networks of leather for further interlocking, which enhanced the thermal stability and the lubricating degree of crust leather and, as a result, the tensile and tear strengths were significantly improved by 79.3% and 25.3%, respectively. Therefore, the use of LMC can promote the widespread application of BPA tanned leather, benefiting to the complete elimination of hazardous Cr pollution.
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ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Jianli Zhou,Xiaobo Liu,Fang Yuan,Bin Deng,Xiaobin Yu
Chitosanase (EC3.2.1.132) can be used to selectively produce partially acetylated chitosan oligosaccharides (COSs), which are functional biopolymers that can widely be utilized as environmentally friendly agents, due to their bioactive, nontoxic, nonallergenic, and biodegradable properties. Different chitosanases can give rise to hydrolysates with diverse functions, making the development of novel chitosanases of great importance in applied biotechnologies. Here, we successfully expressed a novel chitosanase derived from Aspergillus fumigatus CJ22-326 in Pichia pastoris GS115, which could controllably produce chitosan oligosaccharides with desirable polymeric degrees. After glycosylation, the sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the recombinant enzyme Csn75 showed two specific protein bands with sizes of 25.5 and 23.5 kDa individually. The activity of the glycosylated Csn75 was 3.6-fold of that of the deglycosylated Csn75, indicating that glycosylation can greatly increase the activity. Km and Vmax values of the purified Csn75 were 0.46 mg/mL and 6.03 μmol·mL–1·min–1 separately, revealing a good affinity and high catalytic efficiency to the substrate. Moreover, biochemical tests confirmed that Csn75 had the highest activity from 55 to 65 °C when pH ranged from 5.0 to 6.0 and exhibited 4-fold activity in the presence of 1 mM Mn2+. Interestingly, the hydrolysis rate of the crude Csn75 (30 U/mL) can reach up to 90.65% in 4 h when using 2% chitosan as the substrate, producing a mixture of COS with desirable degrees of polymerization (DP), which significantly inhibited the mycelium growth of phytopathogenic fungi. This study proved Csn75 to be a promising chitosanase for the preparation of desirable chitosan oligosaccharides that are green biocides applicable for sustainable agricultural production and environmental protection.
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COLLOIDS AND SURFACES B-BIOINTERFACES
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2020
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IF 4.389
Wenzhong Dai,Chengcheng Ruan,Yue Sun,Xueling Gao,Jin Liang
In order to investigate the influence of different embedding methods on the properties and function of polyphenols, the Epigallocatechin gallate (EGCG) loaded chitosan nanoparticles prepared with or without β-lactoglobulin (β-Lg) were obtained by ionic cross linking method. The average particle sizes of EGCG loaded chitosan nanoparticles (EGCG-CS NPs) decreased from 190 nm to 157 nm after adding with β-Lg, whereas the encapsulation efficiency (EE) increased from 59.79 % to 76.29 %. The results of transmission electron microscopy (TEM) showed that the obtained nanoparticles had obvious core-shell structure. The results of simulated gastrointestinal digestion showed that the release rate of EGCG in CS/β-Lg NPs was much lower than that of CS-NPs. Compared with free EGCG, the DPPH and FRAP assay showed that EGCG-CS NPs and EGCG-CS/β-Lg NPs had slow-controlled antioxidant activity. Meanwhile, the study of cellular antioxidant activity (CAA) showed that the EC 50 values of EGCG-CS NPs and EGCG-CS/β-Lg NPs were decreased by 8.56 % and 18.35 %, respectively.
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RSC Advances
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2020
·Vol. 10
·期 3
·1309-1318
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IF 3.119
Rengui Weng,Xin Huang,Dongqi Liao,Sheng Xu,Lei Peng,Xinzhong Liu
Bamboo cellulose (BC) is one of the most abundant renewable, hydrophilic, inexpensive, and biodegradable organic materials. The cellulose membrane is one of the best materials for replacing petroleum-based polymer films used for water purification. In this study, N-methylmorpholine-N-oxide (NMMO) was used as a solvent to dissolve cellulose and chitosan, and a regenerated cellulose/chitosan membrane (BC/CSM) was prepared by phase inversion. A new kind of cellulose/chitosan nanofiltration membrane (IP-BC/CS-NFM) was obtained by the interfacial polymerization of piperazine (PIP) and trimesoyl chloride (TMC). The IP-BC/CS-NFM was characterized by Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), thermal gravimetric analysis (TGA), the retention rate, and water flux. FT-IR analysis showed that polypiperazine amide was formed. Additionally, FE-SEM and AFM showed that a uniform roughness and dense functional layer was formed on the surface of the IP-BC/CS-NFM. Furthermore, TGA analysis showed that the thermal stability of IP-BC/CS-NFM is better than that of BC/CSM. The inorganic salt retention of IP-BC/CS-NFM was measured using a membrane performance evaluation instrument, following the order R(Na2SO4) > R(MgSO4) > R(MgCl2) > R(NaCl). At a pressure of 0.5 MPa, the retention rates for NaCl, Na2SO4, MgSO4, MgCl2, Methyl Orange, and Methyl Blue were 40.26%, 71.34%, 62.55%, 53.28%, 93.65%, and 98.86%, and the water flux values were 15.64, 13.56, 14.03, 14.88, 13.28, and 12.35 L m−2 h−1, respectively. The IP-BC/CS-NFM showed better water flux and a higher rejection rate in aqueous dye-salt solutions, and had a good separation performance under different operating pressure conditions.
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CARBOHYDRATE POLYMERS
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2020
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IF 7.182
Yupei Li,Jiameng Li,Zhenqiang Shi,Yilin Wang,Xin Song,Liya Wang,Mei Han,Heyue Du,Chao He,Weifeng Zhao,Baihai Su,Changsheng Zhao
Here, we describe a green approach to fabricate genipin crosslinked chitosan-kappa-carrageenan composite hydrogels (C-K hydrogels) aiming at reducing endotoxin level and bacteria burden in septic blood synchronously. The chemical compositions and morphologies of the developed C-K hydrogels were characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy. The C-K hydrogels significantly inhibited adverse blood-material interactions such as hemolysis, complement activation, platelet activation and contact activation, and exhibited better anticoagulant properties than raw chitosan hydrogels. Most importantly, the optimized C 2 -K 1 hydrogels were competent to eliminate 63.3 % of endotoxin in septic blood with a maximum adsorption capacity of 95.0 EU/g during a 3-h simulative hemoperfusion procedure. Bacteria cleansing experiments further demonstrated that the optimized C 2 -K 1 hydrogels effectively decreased 46.0 % of E. coli and 68.7 % of S. aureus load, respectively. It is believed that the C-K hydrogels are promising hemoperfusion sorbents to treat severe septic patients.
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Food and Bioprocess Technology
·
2020
·Vol. 13
·期 6
·1024-1034
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IF 3.356
Wang Qian,Zhang Li,Ding Wu,Zhang Dequan,Reed Kevin,Zhang Boce
This study aimed to develop self-assembled gelatin-chitosan (Gel-CS) nanocapsules as a water-soluble delivery system for alcohol-soluble compounds. Eugenol (Eug) selected as the model molecule for its high solubility in alcohol and insolubility in water. The study also examined different reaction conditions and reagent loading ratios to optimize eugenol-embedded gelatin-chitosan nanocapsules (Eug-Gel-CS NPs) formation. The optimal loading ratio of Gel, CS, and Eug was 3:1:2, which yielded an average particle size of 229.09 nm and an encapsulation efficiency of 50.69%. The morphological characteristics of Eug-Gel-CS NPs were further demonstrated by transmission electron microscopy. The prepared Eug-Gel-CS NPs also exhibited potential controlled-release properties in aqueous phase with the in vitro release percentage of 69.47 ± 1.24% over 36 h. This nanocapsule system may provide a platform to expand the potential applications of Eug in food and nutrition.
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ELECTROCHIMICA ACTA
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2020
·
IF 6.215
Xue Wang,Mengjia Li,Shuang Yang,Jiajia Shan
An electrochemical sensing platform based on TiO 2 –Ti 3 C 2 T X nanohybrid, hexadecyl trimethyl ammonium bromide (CTAB) and chitosan (CS) modified glassy carbon electrode (GCE) has been developed for the detection of nitrite. The TiO 2 –Ti 3 C 2 T X nanohybrid was synthesized by a two-step calcination process. The nanohybrid and its preparation process were characterized by scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Electrochemical methods were used to characterize and investigate the electrochemical behavior and nitrite response of TiO 2 –Ti 3 C 2 T X /CTAB/CS/GCE. Under optimized conditions, the prepared TiO 2 –Ti 3 C 2 T X /CTAB/CS/GCE electrode displayed two linear ranges from 0.003 to 0.25 mM and 0.25 to 1.25 mM with a detection limit of 0.85 μM. Furthermore, the practical applicability of the electrochemical sensor was validated by the detection of nitrite in water and milk samples with good recovery.
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ACS Applied Polymer Materials
·
2020
·
IF 0
Xinran Wei,Ke Ma,Yongbin Cheng,Leyun Sun,Daijun Chen,Xiaoli Zhao,Hao Lu,Botao Song,Kewu Yang,Pengxiang Jia
In addition to conductivity, recent evidence suggests that adhesive, self-healing, and antibacterial properties are also important aspects of wearable force sensors. However, preparation of hydrogel with these combined aspects in a facile strategy is still a challenge. In this paper, a simple method is proposed to obtain adhesive, conductive, self-healing, and antibacterial chitosan–polyoxometalate (POM) hydrogel. First, silicotungstic acid (SiW) was added into a chitosan solution to form a chitosan–silicotungstic acid (CS/SiW) physical cross-link network. Second, the CS/SiW–poly(acrylamide) (PAM) double-network hydrogels were fabricated by the in situ polymerization of acrylamide (AM). The CS/SiW-PAM hydrogel indicated excellent repeatable adhesive capacity on the surface of various materials. The CS/SiW-PAM hydrogel also displayed highly sensitive conductivity upon strain. Moreover, the CS/SiW-PAM hydrogel had outstanding self-healing and antibacterial properties. As a result, it is envisioned that the present work will broaden the path for development of POM-based functional soft materials for various applications.
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Advances in Materials Science and Engineering
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2020
·
IF 1.271
Kai Wang,Haosheng Wang,Su Pan,Chuan Fu,YuXin Chang,Hongru Li,Xiaoyu Yang,Zhiping Qi
Chitosan (CS) is a natural polymer with applications in wound restorations and coatings for artificial implants. However, the lack of antimicrobial activity restricts its further application. Thus, the purpose of this study is to prepare CS/AuNPs film by adding gold nanoparticles (AuNPs) to modify chitosan. Through transmission electron microscopy, we found that the presence of CS can effectively prevent the agglomeration of nanoparticles. Furthermore, through the CCK experiment, we found that AuNPs at a certain concentration can improve the adhesion and proliferation of cells, which has also been proved in animal experiments, including gross appearance, histological observations, and immunofluorescence staining. Such findings support the feasibility of using the film as a promising candidate for tissue engineering of skin in a near future.
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FOOD CHEMISTRY
·
2020
·
IF 6.306
Bing Xie,Xingzhong Zhang,Xiaogang Luo,Yixiang Wang,Yan Li,Bin Li,Shilin Liu
In this work, novel edible coating films based on beeswax-in-water (O/W) Pickering emulsions had been investigated. The Pickering emulsions were stabilized with cellulose nanofibrils (CNFs)/carboxymethyl chitosan (CCS). The emulsions with a droplet diameter of around 10 μm had uniform particle size distribution, and the creaming stability was improved with the increasing the contents of CNFs in the complexes, rheological analysis demonstrated that the Pickering emulsions had an elastic gel-like network. Furthermore, free-standing films were obtained when the emulsions were dried at ambient condition, the tensile strength of the coating films could be 5.0 MPa at a strain of 2.2%, and the water vapor permeability (WVP) value was lower than 2 × 10 −7 g∙h −1 ∙m −1 ∙Pa −1 . Moreover, the coating films could inhibit the growth of typical spoilage organisms such as S. aureus or E. coli, it indicated that the coatings films would have promising applications in antiseptic and fresh keeping for berry fruits.
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RSC Advances
·
2020
·Vol. 10
·期 39
·23410-23416
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IF 3.119
Yanyan Chen,Qi Hu,Qiang Wang,Minghui Yu,Xiaoyu Gong,Shenjie Li,Jin Xiao,Yingjie Guo,Guangyu Chen,Xinyu Lai
With the rapid development of commodity circulation, more attention has been paid to the anticounterfeiting technology of commodities, including stability, universality and ease of distinguishing. The authors report the use of gelatin–chitosan–glycerin/QD nanocomposite-functionalized glue for luminescent anti-counterfeiting labels. As the blend and plasticizer, the addition of chitosan and glycerin effectively improved the flexibility and formability of the gelatin–chitosan–glycerin/QD composite films, which show excellent mechanical properties, including high transparency, luminescence and flexibility, and they are easy to prepare on a large scale, providing certain reference values for new anticounterfeiting technology applying a variety of morphologies.
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