Application of Bentonite Clay, Date Pit, and Chitosan Nanoparticles as Promising Adsorbents to Sequester Toxic Lead and Cadmium from Milk

Abstract

Evaluating residual lead (Pb) and cadmium (Cd) levels in food products, especially milk, is critical for product safety and quality. In this purview, the current study aims to determine Pb and Cd concentrations in milk using atomic absorption spectrophotometry and compare their values with international standards. In addition, it aims to remove these metals from milk samples using low-cost, naturally occurring materials, such as bentonite, date pit, and chitosan nanoparticles. The ability of potential adsorbents was also investigated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and transmission electron microscope (TEM). Moreover, their impact on milk’s nutritional properties was considered. The results revealed that most milk samples contained Pb and Cd, with mean values of 0.237 ± 0.179 and 0.041 ± 0.036 mg/kg, respectively. Furthermore, the three possible adsorbents demonstrated high sequestering ability due to their existing functional groups; the adsorption capacity of bentonite to Pb and Cd was 84 and 88%, date pit was 97 and 93%, and chitosan nanoparticles were 82 and 98%, respectively, with no discernible change in milk nutritional contents. In conclusion, the bentonite, date pit, and chitosan nanoparticles were found to be significantly effective and safe in removing hazardous trace elements (Pb and Cd) from contaminated milk. Graphical abstract

Synthesis of Pectin/ Fe 3 O 4 / Bentonite nanocomposite hydrogel and investigation of heavy metal (Pb 2+ , Cu 2+ , and Cd 2+ ) adsorption properties from water

“…The deformation of the O-H bond of the water molecules in the small band at 1640 cm -1 is seen. Also, OH stretching bands are observed in the 3628 cm -1 bands [7]. In the spectrum of pectin, the C-H bending vibration can be observed in the peak around 551 cm -1 .…”

“…Also, cadmium leads to persistent rhinitis, eosinophilia, non-hypertrophic emphysema, anosmia, anemia, and persistent osteoporosis. Copper also causes digestive disorders [4][5][6][7]. There are various technologies for purifying environments contaminated with heavy metals.…”

“…With its distinctive 2:1 structure, it is made of two tetrahedral sheets and an octahedral sheet placed between them. Bentonite is an effective adsorbent, which is very suitable for the adsorption process due to its chemical and mechanical stability, increased adsorption potential, natural abundance, and the net negative charge on the surface generated by isomorphic replacements inside the octahedral sheets [7,19]. This study aimed to synthesize pectin/Fe3O4/bentonite nanocomposite to investigate its adsorption properties.…”

Optimization study of the adsorption of malachite green removal by MgO nano-composite, nano-bentonite and fungal immobilization on active carbon using response surface methodology and kinetic study

“…The bands at 458 and 513 cm −1 are attributed to (Al-O-Fe) and (Al-O-Si) bending vibrations, respectively [32]. Abdelnaby et al [44] found that bond O-H deformation of the contained water molecules in the silicate matrix is related to the small band at 1633 cm −1 . The band at 1428.18 cm −1 corresponds to the bending vibration of the Al-OH and Si-OH bonds in the octahedral and tetrahedral sheets of the bentonite structure.…”

“…5. The surface of raw bentonite has a porous structure which increases the contact area and promotes adsorption at active sites of the positively charged ions [44]. It is evident that bentonite clay particles were made up of heterogeneous aggregates of assorted sizes and shapes.…”