دانلود رایگان مقاله انگلیسی حذف یون های فلزات سنگین از آب با استفاده از شناور بودن یون - الزویر 2017

Abstract

The effects of different single-chain surfactants obtained by reacting cysteine with octanoyl (C8), decanoyl (C10) and dodecanoyl (C12) chloride were investigated for their use in ion flotation removal of low levels of arsenic, mercury, lead, cadmium and chromium ions from aqueous solution. Re-crystallized octanoyl-cysteine (octanoyl-cys) surfactant showed the highest removal efficiency at 99.9%, for Hg ions, using pure nitrogen gas. Successful removal results of most other ions was found to be in the range 99.1-99.7%, using either air or nitrogen gas. Characterization of the octanoyl-cys surfactant was also carried out using elemental analysis, 1 H NMR, FT-IR, melting point (MP) and critical micelle concentration (CMC) determination.

4. Conclusion

This study has shown that a simple ion flotation process can be used for the efficient removal of arsenic, mercury, lead, cadmium and chromium ions from an aqueous solution, in a single stage physicochemical process. Polluted groundwater, at the 5 mg L-1 level of heavy metal contamination can be treated by this process to give acceptable levels of about 0.01 mg L-1, in a simple process which uses low energy consumption and small space requirements. This process does not require the use of expensive technology, and can be conducted in one step, even at the point of access to the contaminated water. Furthermore, the amino-acid surfactant (cysteinesurfactant), identified as a suitable binding surfactant, is environmentally friendly and biodegradable.