Zeolitic imidazolate framework-8/layered triple hydr(oxide) composite for boosting the adsorptive removal of acid red 1 dye from wastewater

Water pollution is one of the serious environmental problems the humanity currently faces. Adsorption is an attractive process for tackling water pollution. Accordingly, novel adsorbents were synthesized in this study through the coupling of zeolitic imidazolate framework-8 (ZIF-8) with MnCuAl layered triple hydroxide/oxide (MnCuAl-LTH/MnCuAl-LTO) via different approaches. The synthesized adsorbents were characterized using different techniques in order to reveal their textural properties, crystallinity, and functional groups before applying them to decontaminate wastewater samples contaminated with acid red 1 (AR1) azo dye. The BET results revealed that all the synthesized materials are highly porous with specific surface area ranging from about 35 to more than 1200 m2/g. 2 /g. Additionally, the XRD and FTIR results confirmed the formation of the targeted pristine and composite adsorbents. Preliminary adsorption studies showed that the ZIF-8@MnCuAl-LTH composite is the most effective material in removing AR1 from wastewater. Potential mechanism(s) for the superiority of ZIF-8@MnCuAl-LTH over other adsorbents (i.e., MnCuAl-LTH@ZIF-8, MnCuAl-LTO@ZIF-8, MnCuAlLTH, MnCuAl-LTO, and ZIF-8) has been discussed. The results also demonstrated that the adsorption of AR1 onto ZIF-8@ MnCuAl-LTH is strongly pH-dependent. The adsorption isotherm results confirmed that the removal of AR1 is best fitted by the Redlich-Paterson isotherm with a high degree of compatibility with the Langmuir isotherm model. Similarly, the experimental data were well-fitted to the Avrami model, confirming the complex nature of AR1 adsorption onto ZIF-8@ MnCuAl-LTH. Additionally, the regenerability and stability of this adsorbent have been investigated, and the obtained results revealed that this adsorbent is stable and has a good reusability. Accordingly, the ease of fabrication, high adsorption capacity (q max is about 1000 mg/g), and the good stability and reusability make ZIF-8@MnCuAl-LTH a very promising adsorbent for removing anionic azo dyes from wastewaters, demonstrating the significance of this study.