## 3 Results and Discussion  
### Morphological and Structural Investigations  
The SEM analysis of the prepared spiny-like spherical copper metal-organic frameworks (SSC-MOFs) showed a uniform sample structure with a spherical shape which exhibited dimensions between 20 \(\upmu\)m and 30 \(\upmu\)m (Figure 1A,B). The EDS (Figure 1C) analysis confirmed the presence of C, Cu, N and O as the main surface elements on the formed SSC-MOFs owing to the rich presence of heteroatoms on the adsorbent surfaces, which were expected to enhance the separation application. The TEM analysis showed the structure of the formed SSC-MOFs to be parallel, as well as showing interconnected stalks with widths of about 40 nm and lengths between 300 nm and 400 nm (Figure 2A,B). In addition, pores and cavities between the interconnected stalks in the entire SSC-MOF structure were noted, indicating the porous structure of the formed adsorbent materials. The imidazole ligand possesses two nitrogen centers; thus, it can act as an effective interactive attraction site for the copper ions to form a framework during the synthesis process. It was reported that the imidazole-derived ligands enhance the formation of porous metal-organic framework structures [60; 61; 62]. The formation of SSC-MOFs with interconnected stalks and spiky, spherical surfaces is recommended to enhance the dispersion of the SSC-MOFs in an aqueous solution and provide efficient contact with the entire sample extract during the microextraction process for the adsorption and preconcentration of arsenic(III) from water and food sample extracts. The porous nature of the formed SSC-MOFs was confirmed via a BET surface area analysis via the adsorption/desorption of N\({}_{2}\) (Figure 3), which indicated a BET surface area of 120.7 m\({}^{2}\).g\({}^{-1}\). Figure 3 shows an adsorption isotherm of mesoporous materials (type IV). The mesoporous structure of the fabricated SSC-MOFs plays an important role in facilitating the separation of pollutants via the adsorption/desorption mechanism during the microextraction process. The mesoporous structure enables the migration of the adsorbed analyte inside the pores, which improves the adsorption capacity of the material and enhances the applicability for preconcentration purposes [63; 64]. The capacity of the fabricated SSC-MOFs to adsorb arsenic(III) is reported to be 187.3 mg\(\cdot\)g\({}^{-1}\), indicating their high level of efficiency for separating arsenic(III) from aqueous solutions.  
The fabricated SSC-MOFs were analyzed via FTIR to identify the active sites on their surfaces, and the obtained spectrum is presented in Figure 4. A C=N peak was detected at around 1670 cm\({}^{-1}\) due to the imidazole ligand. In addition, strong N-H stretching was detected between 3300 cm\({}^{-1}\) and 3600 cm\({}^{-1}\), which is believed to be derived from the free imidazole ends. Peaks relating to C-N stretching were found in the region between 1100 cm\({}^{-1}\) and 1400 cm\({}^{-1}\). The XRD analysis confirmed the crystalline structure of the formed SSC-MOFs, with peaks at 26 of 10.8, 11.3, 15.6, 16.5, 18.7, 19.9, 20.3, 32 and 34, as presented in the inset graph (Figure 5), in addition to the patterns detected at 37.4, 43.5, 76.9 and 81.17 [65; 66; 67]. These results indicate that the copper ions inside the MOF structure may have more than one transition state, which may be due to the occurrence of a co-ordination with oxygen atom in water molecules simultaneously with bonding formed to nitrogen from the imidazole ligand [66; 68].