ABSTRACT
It is known that wastewaters containing dyes are very difficult to treat, since many dyes are stable and recalcitrant molecules. In this way, sorption may suitable for effectively remove dyes in this specific application field. In this work, a first approach for using polymeric membranous collagen of fish scales for sorption of saline methylene blue dye (MB) solution found in subsurface procedures of oil well industry. From structural characterization, the sorbent was found to be a composite of fibrillar type I collagen and apatites. The MB sorption amounts decreased with temperature increasing, with maximum MB sorbed of 2.18 mmol g-1 at 25 0C. In most sorption tests, residual MB in saline water was undetectable within 200 min of contact time. The sorption kinetic data were well adjusted to a three-parameter multi-step exponential function. The good fitting of such function were only obtained taking into account the presence of time-dependent kinetic parameters. The proposed multi-step sorption mechanism involved surface interaction and diffusion of MB into the membranous collagen. The interaction of positively charged MB ions with the collagenous adsorbent occurred through electrostatic forces. The results point out the collagenous adsorbent for effective procedures of sorption of MB dyes from high-saline wastewaters.
Keywords
Biosorption; membranous adsorbents; high-saline water; multi-step kinetics; oil well
