Design and preparation of ZnCo bimetallic metal-organic framework decorated on cellulose nanocrystals/magnetic graphene oxide for amoxicillin removal from aqueous solution

Abstract

Background

Recently cellulose nanocrystals (CNCs) based nanocomposites have attracted considerable attention in the water treatment area owing to their special features like low cost, environmentally friendly, easy modification, etc. Considering these, as well as the importance of the removal of the antibiotic from water, for the first time, this research work aims to focus on the development of a new nanocomposite of ZnCo bimetallic metal-organic framework decorated on CNCs/magnetic graphene oxide (CNCs/MOF(Zn-Co)/MG) for use in water treatment. Although to date, many efforts have focused on the design of new CNCs based nanocomposites, according to our knowledge, to this day, there has been no study on the preparation and use of CNCs/MOF(Zn-Co)/MG as the amoxicillin (AMX) adsorbent.

Method

CNCs/MOF(Zn-Co)/MG was prepared for the first time through the surface modification of prepared CNCs via in situ MOF(Zn-Co) growth which the CNCs/MOF(Zn-Co) was then hybridized with MG. Batch adsorption studies were performed to explore the potential of CNCs/MOF(Zn-Co)/MG for AMX removal from the aqueous solution.

Significant findings

The textural and structural properties of the CNCs/MOF(Zn-Co)/MG were explored by using various techniques, namely by X-ray diffraction (XRD), Fourier-transform infrared (FT-IR), and energy dispersive X-ray (EDX) analyses. Meanwhile, the surface changes of rice husk due to bleaching, FeCl₃ catalyzed citric acid hydrolysis, MOF(Zn-Co) growth, and composition with MG were monitored employing scanning electron microscopy (SEM). Brunauer-Emmett-Teller (BET) result obtained a mean pore diameter of ∼6.19 nm for CNCs/MOF(Zn-Co)/MG. Specifically, the introduction of the magnetic material, MG in the structure of the final nanocomposite resulted in a magnetic construct with a magnetic saturation of 22.79 emu/g. The outcomes of the batch adsorption tests displayed a 57.22 % AMX removal rate after 5 h when the concentration of AMX was 100 mg/L, pH was 7, and the mass of newly developed CNCs/MOF(Zn-Co)/MG was about 60 mg. The isotherm and kinetic studies verified that the adsorption was fitted with the Freundlich isotherm and the pseudo-first-order models. It also was established that the CNCs/MOF(Zn-Co)/MG could be reused with an acceptable removal efficiency in five cycles which is a good sign of the system benefit from the economic viewpoint. Overall the findings can offer insights into the applicability of eco-friendly CNCs/MOF(Zn-Co)/MG nanocomposite in water treatment.