An eco-friendly cellulose support functionalized with tin titanate nanoparticles for the fast removal of clonazepam drug from the drinking water: adsorption mechanisms

This research studied the performance of tin titanate (SnTiO3, SnT) and cellulose-based composites for the removal of clonazepam (CZP) drug by physical adsorption. The cellulose was extracted from a plant named tithonia tubaeformis, which is considered as weed in the crop fields of Mexico. The analysis by microscopy revealed that the SnTiO3 powders are formed by a mixture of coalesced grains and nanotubes with lengths in the range of 97-633 nm. Furthermore, the X-ray diffraction analysis indicated that the SnT powders present a mixture of cassiterite and rutile phases. Experiments for the CZP removal from drinking water were carried out, and several parameters such as initial drug concentration (1-10 mg/L), amount of SnT adsorbent per liter of contaminated solution (10-50 mg/L), and pH (3-10) were varied in order to study their influence on the CZP removal percentage. Essentially, we found that the SnT dosage of 50 mg/L produced the most efficient and fastest CZP removal, since 94.3% of CZP was removed after only 10 min of reaction. Moreover, a piece of cellulose (Cell) was decorated with 50 mg of SnT powder to form the Cell+SnT composite, and this was able to remove a maximum of 80.5% of CZP after 180 min of reaction. If the amount of SnT powder deposited on the Cell+SnT composite is raised up to 100 mg, the composite can remove 95.5% of CZP. The adsorption capacity was also calculated for the SnT powders and Cell+SnT composite and found that it was 6.3 times higher for the SnT powders. Furthermore, the Raman spectra recorded for the Cell+SnT composites demonstrated the presence of surface defects, which acted as adsorption centers for the CZP molecules. The results of this investigation demonstrate that eco-friendly and low-cost floatable composites can be used for the removal of pharmaceutical contaminants, which is an advantage over adsorbent powders.

Automated summary

This study investigated the performance of tin titanate (SnTiO3, SnT) and cellulose-based composites in removing clonazepam (CZP) drug by physical adsorption. The SnTiO3 powders consisted of coalesced grains and nanotubes, while X-ray diffraction analysis showed a mixture of cassiterite and rutile phases. The optimal dosage of SnT for CZP removal was found to be 50 mg/L, achieving 94.3% removal in just 10 minutes. The Cell+SnT composite, with 50 mg of SnT powder, removed a maximum of 80.5% CZP after 180 minutes, increasing to 95.5% with 100 mg of SnT powder. The adsorption capacity of SnT powders was also found to be 6.3 times higher than that of the Cell+SnT composite. The presence of surface defects in the Cell+SnT composites demonstrated their effectiveness as adsorption centers for CZP molecules. This study highlights the potential of eco-friendly and low-cost floatable composites for pharmaceutical contaminant removal, offering advantages over adsorbent powders.