纳米级零价铁(nZVI)的快速钝化和聚集严重限制了其在废水中不同污染物的修复中的性能。为了克服这些问题,在本研究中,用废弃的花生壳和绿色络合剂柠檬酸钠(SC)制备的生物炭(BC)同时改善了纳米钯/铁(nPd/Fe)。为此,成功合成了一种复合材料(SC-nPd/Fe@BC),用于去除废水中的2,4-二氯苯酚(2,4-DCP)。在SC-nPd/Fe@BC中,BC作为载体与分散的nPd/Fe颗粒,以有效地防止其团聚,并增加了复合材料的比表面积,从而提高了nPd/Fe的反应性和稳定性。表征结果表明,SC-nPd/Fe@BC复合材料分散良好,并且团聚被削弱。颗粒表面钝化层的形成受到抑制,阐明了SC和BC提高nPd/Fe反应活性的机理。发现不同因素影响2,4-DCP的还原二氯化,包括Pd负载,Fe:C,SC加法,温度,初始pH值,和初始污染物浓度。脱氯结果表明,BC和SC的协同作用使SC-nPd/Fe@BC对2,4-DCP的去除效率和脱氯率达到96.0%和95.6%。分别,优于nPd/Fe(去除率:46.2%,脱氯率:45.3%)。动力学研究解释了2,4-DCP的脱氯反应和数据用伪一级动力学模型更好地表示。反应速率常数遵循SC-nPd/Fe@BC(0.0264min-1)>nPd/Fe@BC(0.0089min-1)>SC-nPd/Fe(0.0081min-1)>nPd/Fe(0.0043min-1)的顺序。因此,SC-nPd/Fe@BC能够有效还原2,4-DCP,并且BC和SC协同辅助复合材料在2,4-DCP上的脱氯效率明显优于SC-nPd/Fe,nPd/Fe@BC和nPd/Fe。研究结果表明,SC-nPd/Fe@BC有望有效处理氯化污染物。
Rapid passivation and aggregation of nanoscale zero-valent iron (nZVI) seriously limit its performance in the remediation of different contaminants from wastewater. To overcome such issues, in the present study, nano-palladium/iron (nPd/Fe) was simultaneously improved by biochar (
BC) prepared from discarded peanut shells and green complexing agent sodium citrate (SC). For this purpose, a composite (SC-nPd/Fe@
BC) was successfully synthesized to remove 2,4-dichlorophenol (2,4-DCP) from wastewater. In the SC-nPd/Fe@
BC,
BC acts as a carrier with dispersed nPd/Fe particles to effectively prevent its agglomeration, and increased the specific surface area of the composite, thereby improving the reactivity and stability of nPd/Fe. Characterization results demonstrated that the SC-nPd/Fe@BC composites were well dispersed, and the agglomeration was weakened. The formation of the passivation layer on the surface of the particles was inhibited, and the mechanism of SC and BC improving the reactivity of nPd/Fe was clarified. Different factors were found to influence the reductive dichlorination of 2,4-DCP, including Pd loading, Fe:C, SC addition, temperature, initial pH, and initial pollutant concentration. The dechlorination results revealed that the synergistic effect of the BC and SC made the removal efficiency and dechlorination rate of 2,4-DCP by SC-nPd/Fe@BC reached to 96.0 and 95.6%, respectively, which was better than that of nPd/Fe (removal: 46.2%, dechlorination: 45.3%). Kinetic studies explained that the dechlorination reaction of 2,4-DCP and the data were better represented by the pseudo-first-order kinetic model. The reaction rate constants followed the order of SC-nPd/Fe@
BC (0.0264 min-1) > nPd/Fe@
BC (0.0089 min-1) > SC-nPd/Fe (0.0081 min-1) > nPd/Fe (0.0043 min-1). Thus, SC-nPd/Fe@
BC was capable of efficiently reducing 2,4-DCP and the dechlorination efficiency of
BC and SC synergistically assisted composite on 2,4-DCP was much better than that of SC-nPd/Fe, nPd/Fe@BC and nPd/Fe. Findings suggested that SC-nPd/Fe@BC can be promising for efficient treatment of chlorinated pollutants.