Adsorptive Behavior of Cu 2+ and Benzene in Single and Binary Solutions onto Alginate Composite Hydrogel Beads Containing Pitch Pine-Based Biochar.

In this study, we prepared alginate composite hydrogel beads containing various compositions of biochar produced from pitch pine ( Pinus rigida ) for the removal of Cu 2+ and benzene from model pollutant solutions. The properties of the alginate/biochar hydrogel beads were evaluated using scanning electron microscopy, Fourier transform infrared spectroscopy, and Brunauer-Emmet-Teller analyses. Adsorption behavior of alginate/biochar hydrogel beads indicated that the adsorption capacities for Cu 2+ (28.6-72.7 mg/g) were enhanced with increasing alginate content, whereas the adsorption capacities for benzene (20.0-52.8 mg/g) were improved with increasing biochar content. The alginate/biochar hydrogel beads exhibited similar adsorption capacities for Cu 2+ and benzene in the concurrent system with Cu 2+ and benzene compared to those in a single pollutant system. Adsorption kinetics and isotherm studies of the alginate/biochar hydrogel beads followed the pseudo-second-order model (r 2 = 0.999 for Cu 2+ , and r 2 = 0.999 for benzene), and Langmuir model (r 2 = 0.999 for Cu 2+ , and r 2 = 0.995 for benzene). In addition, alginate/biochar hydrogel beads (containing 1 and 4% biochar) exhibited high reusability (>80%). Therefore, alginate/biochar hydrogel beads can be applied as adsorbents for the removal of multiple pollutants with different properties from wastewater.