Mahich Sanju, Saini Yogesh Kumar, Devra Vijay, Aggarwal Kanika, Kumar Anuj, Kumar Dinesh, Singh Amanpal, Arya Yogendra
Department of Physics, University of Rajasthan, Jaipur, Rajasthan, 302004, India.
Janki Devi Bajaj Government Girls College, Kota, Rajasthan, 324001, India.
Heliyon. 2024 May 23;10(11):e31702. doi: 10.1016/j.heliyon.2024.e31702. eCollection 2024 Jun 15.
The release of organic pollutants and dyes into the environment by industries has had profound and harmful effects on both humans and ecosystems. Graphene oxide (GO) and its reduced form have been investigated for their effectiveness in removing pollutant dyes. GO nano-powder was synthesized using an improved version of Hummer's method and subsequently thermally reduced at various temperatures, including 125, 150, 175, and 200 °C, under vacuum conditions. In the X-ray diffraction spectra, an intense (001) diffraction peak was initially observed at 9.136° (2θ) for pristine GO. This peak gradually shifted towards higher angles as the reduction process took place and eventually disappeared when the GO was reduced at 200 °C. The intensity ratio of the D and G bands (ID/IG ratio) for GO nano-powder in the Raman spectra decreased from 0.94 to 0.76 due to the reduction process. The FTIR spectra of GO and reduced graphene oxide (rGO) also illustrated the reduction process. The bandgap of pristine GO significantly decreased from 2.31 to 0.73 eV, as determined by ultraviolet-visible (UV-Vis) diffuse reflectance spectrophotometry during the reduction process. The surface area and pore volume of both pristine GO and rGO-150 were determined using the BET (Brunauer-Emmett-Teller) and BJH (Barrett-Joyner-Halenda) methods. The results indicated an increase in the BET surface area from 6.61 to 7.86 m/g and a corresponding enhancement in pore volume from 0.118 to 0.128 cc/g after reduction. The adsorption and photocatalytic degradation behavior of pristine GO and reduced graphene oxides (rGOs) were examined using methylene blue dye. The pristine GO demonstrated impressive adsorption capability, effectively removing the dye by 85.78 % within just 15 min and achieving nearly 97 % removal after 4 h. In contrast, the highest photocatalytic degradation of methylene blue, about 47.58 %, was attained for the rGO sample reduced at 150 °C under the illumination of visible light.
工业向环境中排放有机污染物和染料对人类和生态系统都产生了深远且有害的影响。人们对氧化石墨烯（GO）及其还原形式去除污染染料的有效性进行了研究。采用改进的Hummer法合成了GO纳米粉末，随后在真空条件下于125、150、175和200℃等不同温度下进行热还原。在X射线衍射光谱中，原始GO最初在9.136°（2θ）处观察到一个强烈的（001）衍射峰。随着还原过程的进行，该峰逐渐向更高角度移动，当GO在200℃还原时最终消失。由于还原过程，GO纳米粉末在拉曼光谱中的D带和G带强度比（ID/IG比）从0.94降至0.76。GO和还原氧化石墨烯（rGO）的傅里叶变换红外光谱（FTIR）也说明了还原过程。在还原过程中，通过紫外可见（UV-Vis）漫反射分光光度法测定，原始GO的带隙从2.31显著降低至0.73 eV。使用BET（Brunauer-Emmett-Teller）和BJH（Barrett-Joyner-Halenda）方法测定了原始GO和rGO-150的表面积和孔体积。结果表明，还原后BET表面积从6.61增加到7.86 m/g，孔体积相应地从0.118增加到0.128 cc/g。使用亚甲基蓝染料研究了原始GO和还原氧化石墨烯（rGOs）的吸附和光催化降解行为。原始GO表现出令人印象深刻的吸附能力，在短短15分钟内有效去除85.78%的染料，4小时后实现近97%的去除率。相比之下，在可见光照射下，150℃还原的rGO样品对亚甲基蓝的光催化降解率最高，约为47.58%。
