Jun Zhong,Wei Zhu,Xin Wang,Jipeng Sun,Biao Mu,Yucheng Xu,Guorui Li
In this study, Fe conversion during hydrothermal carbonization (HTC) of coking sludge were investigated, and the effect mechanism of Fe component on the adsorption performance of coking sludge hydrochar (CHC) was explored. The results showed that after HTC treatment, more than 95 % of Fe remained in the CHC. Fe 3+ was reduced to Fe 2+ by sugar and amino acids . Fe was stabilized during the HTC process and was still predominantly in the Fe manganese oxidation state. The CHC prepared at 270 °C exhibited excellent adsorption capacities for Congo red (CR), tetracycline (TC), and Cr (VI). Their maximum adsorption capacities were 140.85, 147.06, and 19.92 mg/g, respectively. Quantitative adsorption mechanism experiments, XRD and VSM characterization revealed that Fe component played a significant role in adsorption, and CHC with more Fe 3 O 4 exhibited better adsorption capacity. The results of the XPS characterization of CHC before and after adsorption showed that Fe 3 O 4 provided rich Fe adsorption sites on the surface of CHC to strengthen the adsorption efficiency of pollutants through Fe 3+ /Fe 2+ reduction and complexation of Fe-O/N. In addition, the formed Fe 3 O 4 also imparted CHC with magnetic properties (Ms = 4.12 emu/g) to facilitate the subsequent separation and recovery. These results demonstrated that the prepared CHC has great potential for treating actual wastewater containing CR and TC.
Shuang Li,Yao Huang,Junhao Shen,Shengjun Mao,Rong Peng,Hui Liu
The interaction between surface water and groundwater in the riparian zone significantly influences iron (Fe) transformation. This study characterized the Fe mineral composition of sediments collected from the riparian zones upstream and downstream of the Xinglong Dam of Han River, China. The coexistence of divalent (Fe–CO 3 ) and Fe(III) minerals in the sediments suggested varying redox conditions of the riparian zone . Furthermore, the transformation processes of dissolved Fe(II) under different bicarbonate concentrations and surface water-groundwater ratios during the interaction between surface water and groundwater were investigated by laboratory batch experiments to understand the formation of Fe–CO 3 and Fe(III) minerals in the riparian zone. The results demonstrated that elevated bicarbonate concentrations (0–20 mM) and surface water ratios promoted the transformation rate and amount of dissolved Fe(II) to solids. The predominant minerals of the formed solid were lepidocrocite , goethite , and Fe–CO 3 , according to the results of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectroscopy. The rising bicarbonate concentration facilitated Fe–CO 3 synthesis. The Fe(III) mineral (goethite) was more likely to develop when dissolved oxygen (DO) and bicarbonate concentrations were high. The generated hydroxyl radical (•OH) during dissolved Fe(II) oxidation was also increased with elevated HCO 3 − concentration and surface water ratio, indicating higher oxidative potential in the riparian zone with higher bicarbonate and surface water ratio. These findings offer insights into the Fe transformation in redox-fluctuating zones.
Huimin Zhu,Guodong Cao,Chu Qiang,YiKe Fu,Yulian Wu,Xiang Li,Gaorong Han
Nanoparticles presenting promoted catalytic activity, oxygen induction and loading capability are in high demand for effective synergistic tumor therapy. Herein, ferric-tannic acid complex nanocapsules with fine hollow microstructure (HFe-TA) are synthesized and loaded with a photosensitizer (indocyanine green, ICG) for synergistic tumor therapy. In acidic environment, ICG@HFe-TA decomposes and releases Fe3+ ions, TA and ICG molecules. Fe3+, with low catalytic activity, is effectively converted into highly catalytic Fe2+ by the reductant TA, enabling promoted efficacy of ˙OH induction. More importantly, the ROS (1O2) induction by ICG is significantly enhanced under 808 nm laser irradiation due to the O2 byproduct of Fe3+/Fe2+ conversion. In consequence, the ICG@HFe-TA nanoparticles exhibit considerable in vitro and in vivo tumor inhibition owing to the combined effect of ˙OH and 1O2 induced intracellularly. This study has therefore demonstrated a potential platform enabling combined photodynamic and chemodynamic therapy with high efficacy.
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