Rapid and Selective Recovery of Boron from Desalination Waste Using N-Methyl-d-glucamine-Modified Bioadsorbent

Recovering boron (B) from desalination brine is essential for sustainable resource management and meeting critical raw material demands. In this study, we designed and evaluated a novel bioadsorbent, N-methyl-d-glucamine (NMDG)-modified cellulose (MGMC), for selective B recovery from desalination brine. The adsorption kinetics, isotherms, selectivity, and influence of competing salts were examined, along with B recovery from seawater and simulated desalination brine. Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and pH at the point of zero charge (pH_PZC) analysis were used to elucidate the adsorption mechanism. MGMC attained rapid adsorption equilibrium within 0.5 h and exhibited a high B adsorption capacity of 1,647 μmol g^–1, surpassing commercial adsorbents and most previously reported NMDG-modified derivatives. Moreover, MGMC demonstrated excellent selectivity for B, effectively rejecting diverse metals and oxyanions. Furthermore, it achieved ≥97% B sorption from seawater and simulated brine with shorter contact times and lower dosages than commercial resins. MGMC’s outstanding B selectivity is attributed to the strong coordinated interaction between B and the hydroxy groups in its NMDG-rich structure, further aided by a low pH_PZC (6.9). Our findings demonstrate MGMC as a cost-effective and eco-friendly solution for selective B recovery from desalination processes, presenting a promising avenue for sustainable resource management.