In-grown flower like Al-Li/Th-LDH@CNT nanocomposite for enhanced photocatalytic degradation of MG dye and selective adsorption of Cr (VI)

Inner transition metal ions doped layered double hydroxides-embedded in CNTs have attracted increasing attention for wastewater treatment and renewable energy recently. In this work, the nanostructures of Al-Li/Th-LDH@CNT consisting of flower-like morphology were successfully synthesized by the elegant combination of exfoliated Al-Li/Th LDHs nano-sheets and F-CNTs using the hydrothermal method. The as-synthesized Al-Li@ThLDH-CNT nanocomposite is employed for MG dye photodegradation and selective adsorption of Cr (VI) ions. The Al-Li/Th-LDH@CNT nanocomposite has exhibited excellent visible-light-induced photocatalytic activity towards Malachite green (MG) dye, and almost 98% of (MG) dye is decolorized within 45 min. Studies probing the mechanism demonstrate that the photogenerated hydroxyl radical and holes play a vital role in the MG dye degradation process. Furthermore, the Al-Li/Th-LDH@CNT was tested to examine its selective adsorption behavior towards different metal ions at ultra-low trace levels by the ICP-MS technique. The adsorption behavior of Al-Li/Th-LDH@CNT displayed high removal percentage towards Cr6+ (94.1%), while as 86.7% and 83% for Al-Li and Al-Li-CNT adsorbents and the maximum adsorption capacities of Al-Li, Al-Li-CNT, and Al-Li/ Th-LDH@CNT were found to be 156.2, 163.3 and 172.4 mg/g respectively. Thus, preparing layered structure composite using a simple engineered route may open a new strategy to synthesize advanced materials having improved synergistic catalytic properties, which could be effectively used as highly efficient probes for environmental applications.

Automated summary

Doped layered double hydroxides embedded in CNTs have shown promising applications in wastewater treatment and renewable energy. The synthesized Al-Li/Th-LDH@CNT nanocomposite exhibited excellent visible-light-induced photocatalytic activity towards MG dye and selective adsorption behavior towards Cr6+, indicating potential environmental applications.