Takle Shrikant P, Apine Onkar A, Ambekar Jalindar D, Landge Sukeshani L, Bhujbal Namdeo N, Kale Bharat B, Sonawane Ravindra S
Centre for Materials for Electronic Technology, Government of India Panchavati, Off Pashan Road Pune 411008 India
Department of Biotechnology, Shivaji University Kolhapur 416004 India.
RSC Adv. 2019 Feb 1;9(8):4226-4238. doi: 10.1039/c8ra10026h. eCollection 2019 Jan 30.
A dark-coloured effluent called "spent wash" is generated as an unwanted product in sugarcane-based alcohol distilleries. Most distilleries discharge this effluent into soil or water without any treatment, causing water and soil pollution. Herein, we report chromium-doped TiO (Cr-TiO) as a photocatalyst for the degradation of spent wash colour under natural sunlight. Cr-doped TiO nanoparticles were prepared using an aqueous titanium peroxide-based sol-gel method with titanium isopropoxide as the Ti precursor and chromium nitrate as the Cr precursor. To observe the effect of dopant on sol-gel behaviour and physicochemical properties, the Cr concentration was varied in the range 0.5-5 wt%. The crystallization temperature and time were optimized to obtain the required phase of Cr-TiO. The physicochemical characteristics of the Cr-doped TiO catalyst were determined using X-ray diffraction, FE-SEM, FETEM, TG, XPS, the Brunauer-Emmett-Teller (BET) method, FT-IR, Raman, PL, ICP-MS, and UV visible spectroscopy. A shift in the absorption edge of TiO by doping with chromium suggested an increase in visible light absorption due to a decrease in the effective band gap. The application potential of the Cr-TiO catalyst was studied in the degradation of sugar-based alcohol distillery waste under natural sunlight, and the results were compared with those of undoped TiO and Degussa P25 TiO. Degradation of the spent wash solution was monitored using UV-visible, gel permeation chromatography (GPC), and QTOF LC-MS. GPC and LC-MS showed significant changes in the molecular weight of spent wash colour-forming compounds due to the degradation reaction. QTOF LC-MS analysis suggested that acids, alcohols, glucosides, ketones, lipids, peptides, and metabolites were oxidized to low-molecular-weight counterparts. From the results, 5% Cr-TiO showed the highest degradation rate among all Cr-TiO samples, undoped TiO, and Degussa P25 TiO under identical reaction conditions, with nearly 68-70% degradation achieved in 5 h.
在以甘蔗为原料的酒精蒸馏厂中，会产生一种名为“废醪液”的深色废水，它是不需要的产物。大多数蒸馏厂未经任何处理就将这种废水排放到土壤或水中，造成水和土壤污染。在此，我们报道了铬掺杂的二氧化钛（Cr-TiO₂）作为一种光催化剂，用于在自然阳光下降解废醪液的颜色。采用以过氧化钛水溶液为基础的溶胶-凝胶法，以异丙醇钛为钛前驱体、硝酸铬为铬前驱体，制备了铬掺杂的TiO₂纳米颗粒。为了观察掺杂剂对溶胶-凝胶行为和物理化学性质的影响，将铬浓度在0.5-5 wt%范围内变化。对结晶温度和时间进行了优化，以获得所需的Cr-TiO₂相。采用X射线衍射、场发射扫描电子显微镜（FE-SEM）、场发射透射电子显微镜（FETEM）、热重分析（TG）、X射线光电子能谱（XPS）、布鲁诺尔-埃米特-泰勒（BET）法、傅里叶变换红外光谱（FT-IR）、拉曼光谱、光致发光（PL）、电感耦合等离子体质谱（ICP-MS）和紫外可见光谱等方法，对铬掺杂的TiO₂催化剂的物理化学特性进行了测定。通过铬掺杂使TiO₂的吸收边发生位移，这表明由于有效带隙减小，可见光吸收增加。研究了Cr-TiO₂催化剂在自然阳光下对糖基酒精蒸馏厂废水的降解应用潜力，并将结果与未掺杂的TiO₂和德固赛P25 TiO₂进行了比较。使用紫外可见光谱、凝胶渗透色谱（GPC）和四极杆飞行时间液相色谱-质谱联用仪（QTOF LC-MS）监测废醪液的降解情况。GPC和LC-MS显示，由于降解反应，废醪液中呈色化合物的分子量发生了显著变化。QTOF LC-MS分析表明，酸、醇、糖苷、酮、脂质、肽和代谢物被氧化为低分子量的对应物。结果表明，在相同反应条件下，5% Cr-TiO₂在所有Cr-TiO₂样品、未掺杂的TiO₂和德固赛P25 TiO₂中表现出最高的降解率，在5小时内实现了近68-70%的降解。
