Efficient Adsorption of Chromium Ions from Aqueous Solutions by Plant-Derived Silica

Nowadays, there is great interest in the use of plant waste to obtain materials for environmental protection. In this study, silica powders were prepared with a simple and low-cost procedure from biomass materials such as horsetail and common reed, as well as wheat and rye straws. The starting biomass materials were leached in a boiling HCl solution. After washing and drying, the samples were incinerated at 700 degrees C for 1 h in air. The organic components of the samples were burned leaving final white powders. These powders were characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), scanning electron microscopy (SEM), and low-temperature nitrogen sorption. The amorphous powders (biosilica) contained mainly SiO2, as indicated by FTIR analysis. Horsetail-derived silica was chosen for testing the removal of dichromate ions from water solutions. This biosilica had a good ability to adsorb Cr(VI) ions, which increased after modification of the powder with the dodecylamine surfactant. It can be concluded that the applied procedure allowed obtaining high purity biosilica from plant waste with good efficiency. The produced biosilica was helpful in removing chromium ions and showed low cytotoxicity to human endothelial cells, suggesting that it can be safely used in environmental remediation.

Automated summary

There is a growing interest in using plant waste for environmental protection materials. This study focused on preparing silica powders from various biomass materials, such as horsetail, common reed, wheat, and rye straws. The powders were obtained through a simple and low-cost procedure, which involved leaching the biomass materials in a boiling HCl solution, incinerating the samples, and removing the organic components. The resulting biosilica powders showed high purity and mainly consisted of SiO2. The horsetail-derived biosilica exhibited good adsorption capacity for removing Cr(VI) ions from water, particularly after surface modification with a surfactant. The biosilica also demonstrated low cytotoxicity to human endothelial cells, indicating its potential for safe use in environmental remediation.