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The biosorption of Cd(II) and Cr(VI) ions from aqueous solutions using Pensi (Corbicula moltkiana) shell activated with HNO 3 0,01 M was studied in batch method. The optimum conditions were reached at concentration 100 mg/L, particle size 32 µm, and biosorbent mass 0.1 gram for both Cd(II) and Cr(VI) ions. At pH 6 and contact time 120 minutes, biosorbent was warmed at 28 o C with the sorption capacity of 6.073 mg/g for Cd(II), while at pH 3, contact time 15 minutes, biosorbent was warmed at 80 o C with the sorption capacity of 1.286 mg/g. The adsorption of Cd(II) and Cr(VI) ions follows the Langmuir isotherm models with R 2 0.9389 for Cd(II) ions and 0.9972 for Cr(VI) ions. The Langmuir Isotherm Method indicates an adsorption process occurrs as chemicals formed monolayer. This result showed that Pensi shell can be used to overcome Cd(II) and Cr(VI) content in wastewater.

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Detection of bio chemical species in a liquid is very important for research and technical purposes. In the last decade, metallic nanoparticles have been shown to be potential for such measurement. Resonance wavelength (or frequency) of free electron oscillation on metallic nanoparticle surface is very sensitive to tiny changes of its surrounding environment. Change in surrounding medium shifts the resonance wavelength with a slope determined mainly by the size and geometry of nanoparticle. We numerically optimized size and aspect ratio of silver and gold nanoparticles to obtain the highest sensing sensitivity. Here, sensitivity is defined as the slope of resonance wavelength on refractive index of liquid. We found that size, aspect ratio, and material of metal affect sensing sensitivity of metal nanoparticle based sensor significantly.