ABSTRACT

Cesium radioisotopes are among the majors that are presented in liquid radioactive waste causing long-term environmental threats. The mandatory treatment of these streams is regenerative goal in which adsorption techniques are focal. Calcium alginate/graphene-sodium dodycyl sulfate (CA/GR-SDS) nanocomposite beads were synthesized/characterized and their sorption properties toward $\mathrm{C}{\mathrm{s}}^{+}$ were evaluated. Beads were of amorphous nature and the essential components were detected by FT-IR. Batch and fixed-bed column studies were explored. The highest sorbed $\mathrm{C}{\mathrm{s}}^{+}$ amounts were acquired within the 1^st- 30 min of contact time. The pseudo 2^nd-order model gave the best fitting of the experimental kinetic data. Simple thermodynamic models have been applied to the isotherm sorption data and the relevant thermodynamic parameters were determined from the graphical presentation of these models. Increasing temperature gave lower quantities of sorption capacities. The estimated thermodynamic parameters disclosed the exothermic spontaneous ease of all sorption processes where negative $\mathrm{\Delta }{H}^o$ and $\mathrm{\Delta }{G}^o$ quantities were gained. Curves of $\mathrm{C}{\mathrm{s}}^{+}$ breakthrough from CA/GR-SDS were constructed at varied bed depths (2.0, 4.0, and 8.0 cm) and flow rates (1.0 and 2.0 mL/min). Increasing the bed depth to 8.0 cm, slower exhaustion time was observed (15.5 h). Capacities and performances of beds were increased from 24.85 to 214.46 mg/g and from 13.67 to 29.89%, respectively, by increasing bed depths from 2.0 to 8.0 cm. A fast exhaustion time were observed with increasing the flow rate to 2.0 mL/min (1.17 h).

摘要

铯放射性同位素是液态放射性废物中存在的主要污染物之一，会对环境造成长期威胁。这些流的强制性处理是再生技术的目标，其中吸附技术是重点。海藻酸钙/石墨烯-十二烷基硫酸钠（CA / GR-SDS）纳米复合小球的合成/表征及其吸附性能$\mathrm{C}{\mathrm{s}}^{+}$被评估。珠子是无定形的，必需成分通过FT-IR检测。探索了分批和固定床色谱柱的研究。最高吸附$\mathrm{C}{\mathrm{s}}^{+}$在接触时间的^第1-30分钟内获得了一定量。伪2^次阶模型给出的实验动力学数据的最佳拟合。已将简单的热力学模型应用于等温线吸附数据，并根据这些模型的图形表示确定了相关的热力学参数。温度升高使吸附容量降低。估计的热力学参数揭示了所有吸附过程的放热自​​发缓解（负值）$\mathrm{\Delta }{H}^{Ø}$ 和 $\mathrm{\Delta }{G}^{Ø}$获得数量。的曲线$\mathrm{C}{\mathrm{s}}^{+}$在不同的床层深度（2.0、4.0和8.0 cm）和流速（1.0和2.0 mL / min）下构建了CA / GR-SDS的突破。将床深增加到8.0 cm，观察到较慢的排气时间（15.5 h）。通过将床层深度从2.0 cm增加到8.0 cm，床层的容量和性能分别从24.85 mg / g增加到214.46 mg / g，从13.67％增加到29.89％。随着流速增加至2.0 mL / min（1.17 h），观察到了快速的排气时间。