Li Zhao,Wei Lv,Juying Hou,Yijing Li,Junling Duan,Shiyun Ai
We synthesized magnetically recyclable g-C 3 N 4 /Fe 3 O 4 /ZIF-8 nanocomposites as an emerging adsorbent for the malachite green (MG) removal in aqueous solution. Bath absorption experiments for MG were done to explore the influence (pH, adsorbent dosage and initial concentration) on its absorption process. The adsorption isotherm and kinetics followed Langmuir model and pseudo-second-order kinetic model, respectively. The thermodynamic datas (ΔG ○ < 0, ΔH ○ > 0, ΔS ○ > 0) showed that the adsorption process for MG was feasible, endothermic and spontaneous. The g-C 3 N 4 /Fe 3 O 4 /ZIF-8 nanocomposites showed excellent removal properties for MG. The maximum equilibrium adsorption capacity could reach as high as 3412 mg/g. The g-C 3 N 4 /Fe 3 O 4 /ZIF-8 nanocomposites could be easily separated using an external magnet, and the nanocomposites could be repeatedly utilized after five cycles. The ultra-high adsorption capacity, easy separation, and excellent recyclability enabled the obtained g-C 3 N 4 /Fe 3 O 4 /ZIF-8 nanocomposites a good adsorbent for the adsorption of MG.
Jiaming Wang,Minxin Shi,Yuanyuan Qin,Yuhua Huang,Xiancai Li,Xiaohua Cao
The enrichment and recovery of low concentration rare earth ions from wastewater resources has become an important research direction to achieve high quality utilization of rare earth resources. In this experiment, graphitic carbon nitride was used as the substrate, which was firstly compounded with Fe 3 O 4 to become magnetic graphitic carbon nitride material by alcohol heat method, and then in situ compounded with ZIF-8 in aqueous phase at room temperature to form the composite g-C 3 N 4 /Fe 3 O 4 @ZIF-8. Finally, the composite was characterized. The adsorption performance of g-C 3 N 4 /Fe 3 O 4 @ZIF-8 and the control g-C 3 N 4 /Fe 3 O 4 and ZIF-8 for La(III) under various conditions was investigated by adsorption experiment. In addition, the types and mechanism of La(III) adsorption were discussed by kinetic, isothermal adsorption line and thermodynamic modeling studies. Finally, the stability performance and reusability of the composite were evaluated by regeneration experiments. The result show that g-C 3 N 4 /Fe 3 O 4 @ZIF-8 has good adsorption performance on lanthanide ions. g-C 3 N 4 /Fe 3 O 4 @ZIF-8 reached adsorption equilibrium at about 20 min. When pH is 6 and the solid–liquid ratio of adsorbent is 0.25 g/L, the adsorption amount was 176.68 mg/g. g-C 3 N 4 /Fe 3 O 4 @ZIF-8 had good selectivity for lanthanum(III), and it retains 81 % of initial adsorption performance after five times of reuse.
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