Over the recent years, the global increase of electronic wastes from electrical and electronic devices (e-wastes) has been on an alarming trend in quantity and toxicity and e-waste<span style="font-family:Verd...Over the recent years, the global increase of electronic wastes from electrical and electronic devices (e-wastes) has been on an alarming trend in quantity and toxicity and e-waste<span style="font-family:Verdana;">s</span><span style="font-family:""><span style="font-family:Verdana;"> are non-biodegradable resulting in its cumulative increase over time. Changes in technology and unrestricted regional movement of electrical devices have facilitated the generation of more e-wastes leading to high levels of air, soil and water pollution. To address these challenges, biodegradable organic components such as chitosan have been used to replace their inorganic counterparts for optoelectronic device applications. However, in-depth knowledge on how such materials can be used to tune the optical properties of their hybrid semiconductors is unrivaled. Thus, systematic studies of the interplay between the preparation methods and optical </span><span style="font-family:Verdana;">band gap and Urbach energy of such organic components are vital. This study has thus been dedicated to map out the effect of acid concentrations</span><span style="font-family:Verdana;"> during chitosan extraction on the corresponding optical band gap and Urbach energy with a view to improving its applications in optoelectronic devices. The,</span></span><span style="font-family:""> </span><span style="font-family:Verdana;">1.0 to 2.5 molar hydrochloric acid (HCl) was used for 12 hours at room temperature during demineralization and 2.0 molar sodium hydroxide (NaOH) during deprotonation processes. The absorbance spectrum of the samples was collected by UV-Vis spectrophotometer and band gap energies were analyzed by performing Tauc’s plot. This study revealed that the energy band gap of chitosan extracted from 1 M HCl, 1.5 M HCl, 2.0 M HCl and 2.5 M HCl were 3.72 eV, 3.50 eV</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> 3.45 eV and 3.36 eV respectively. Furthermore, the Urbach energy of chitosan extracted from 1 M HCl, 1.5 M HCl, 2.0 M HCl and 2.5 M HCl were 0.60496 eV, 0.5292 eV, 4724 eV and 0.2257 eV, respectively.</span>展开更多
制得了系列壳聚糖嫁接的大环席夫碱Cu(Ⅱ)化合物(CTS-Ln-Cu(Ⅱ).通过元素分析、1 H NMR、FT-IR、MS及扫描电镜(SEM)等手段对上述化合物的结构和组成进行了表征.并采用邻苯三酚自氧化法测定了它们的抗氧活性.结果表明,经过嫁接后均具有...制得了系列壳聚糖嫁接的大环席夫碱Cu(Ⅱ)化合物(CTS-Ln-Cu(Ⅱ).通过元素分析、1 H NMR、FT-IR、MS及扫描电镜(SEM)等手段对上述化合物的结构和组成进行了表征.并采用邻苯三酚自氧化法测定了它们的抗氧活性.结果表明,经过嫁接后均具有良好的抗氧活性,其IC50值分别为:15.81,18.82,21.44和19.33×10-3 g.L-1.展开更多
以油茶皂素的提取率作为响应值,用响应面法对既能充分发挥壳聚糖凝聚油茶籽工艺水中杂质,又不影响油茶皂素提取的工艺条件进行优化。在考虑壳聚糖浓度及添加量、反应时间及温度、搅拌速度等因素对油茶皂素提取率影响的基础上,筛选出主...以油茶皂素的提取率作为响应值,用响应面法对既能充分发挥壳聚糖凝聚油茶籽工艺水中杂质,又不影响油茶皂素提取的工艺条件进行优化。在考虑壳聚糖浓度及添加量、反应时间及温度、搅拌速度等因素对油茶皂素提取率影响的基础上,筛选出主要影响因素即壳聚糖添加量、反应时间、反应温度进行正交试验,通过响应面分析,得出3种因素的相互作用及最佳提取条件。结果表明,在壳聚糖浓度为0.05%,搅拌速度为10 r/min,壳聚糖添加量为17.8 m L,反应温度为50.1℃,反应时间为16.6 min的优化条件下,油茶皂素提取率为84.97%。展开更多
文摘Over the recent years, the global increase of electronic wastes from electrical and electronic devices (e-wastes) has been on an alarming trend in quantity and toxicity and e-waste<span style="font-family:Verdana;">s</span><span style="font-family:""><span style="font-family:Verdana;"> are non-biodegradable resulting in its cumulative increase over time. Changes in technology and unrestricted regional movement of electrical devices have facilitated the generation of more e-wastes leading to high levels of air, soil and water pollution. To address these challenges, biodegradable organic components such as chitosan have been used to replace their inorganic counterparts for optoelectronic device applications. However, in-depth knowledge on how such materials can be used to tune the optical properties of their hybrid semiconductors is unrivaled. Thus, systematic studies of the interplay between the preparation methods and optical </span><span style="font-family:Verdana;">band gap and Urbach energy of such organic components are vital. This study has thus been dedicated to map out the effect of acid concentrations</span><span style="font-family:Verdana;"> during chitosan extraction on the corresponding optical band gap and Urbach energy with a view to improving its applications in optoelectronic devices. The,</span></span><span style="font-family:""> </span><span style="font-family:Verdana;">1.0 to 2.5 molar hydrochloric acid (HCl) was used for 12 hours at room temperature during demineralization and 2.0 molar sodium hydroxide (NaOH) during deprotonation processes. The absorbance spectrum of the samples was collected by UV-Vis spectrophotometer and band gap energies were analyzed by performing Tauc’s plot. This study revealed that the energy band gap of chitosan extracted from 1 M HCl, 1.5 M HCl, 2.0 M HCl and 2.5 M HCl were 3.72 eV, 3.50 eV</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> 3.45 eV and 3.36 eV respectively. Furthermore, the Urbach energy of chitosan extracted from 1 M HCl, 1.5 M HCl, 2.0 M HCl and 2.5 M HCl were 0.60496 eV, 0.5292 eV, 4724 eV and 0.2257 eV, respectively.</span>
文摘制得了系列壳聚糖嫁接的大环席夫碱Cu(Ⅱ)化合物(CTS-Ln-Cu(Ⅱ).通过元素分析、1 H NMR、FT-IR、MS及扫描电镜(SEM)等手段对上述化合物的结构和组成进行了表征.并采用邻苯三酚自氧化法测定了它们的抗氧活性.结果表明,经过嫁接后均具有良好的抗氧活性,其IC50值分别为:15.81,18.82,21.44和19.33×10-3 g.L-1.
文摘以油茶皂素的提取率作为响应值,用响应面法对既能充分发挥壳聚糖凝聚油茶籽工艺水中杂质,又不影响油茶皂素提取的工艺条件进行优化。在考虑壳聚糖浓度及添加量、反应时间及温度、搅拌速度等因素对油茶皂素提取率影响的基础上,筛选出主要影响因素即壳聚糖添加量、反应时间、反应温度进行正交试验,通过响应面分析,得出3种因素的相互作用及最佳提取条件。结果表明,在壳聚糖浓度为0.05%,搅拌速度为10 r/min,壳聚糖添加量为17.8 m L,反应温度为50.1℃,反应时间为16.6 min的优化条件下,油茶皂素提取率为84.97%。
