Encapsulation of iron nanoparticles in alginate biopolymer for trichloroethylene remediation

Nanoscale zero-valent iron (NZVI) particles (10-90 nm) were encapsulated in biodegradable calcium-alginate capsules for the first time for application in environmental remediation. Encapsulation is expected to offers distinct advances over entrapment. Trichloroethylene (TCE) degradation was 89-91% in 2 h, and the reaction followed pseudo first order kinetics for encapsulated NZVI systems with an observed reaction rate constant (k (obs)) of 1.92-3.23 x 10(-2) min(-1) and a surface normalized reaction rate constant (k (sa)) of 1.02-1.72 x 10(-3) L m(-2) min(-1). TCE degradation reaction rates for encapsulated and bare NZVI were similar indicating no adverse affects of encapsulation on degradation kinetics. The shelf-life of encapsulated NZVI was found to be four months with little decrease in TCE removal efficiency.