Aquino, Errol B. <br/><br/>
Biosorption of cr(vi) from a queous solution using cao nanoparticles extracted from tahong (asian green mussels) waste shells/ 
Errol B. Aquino, Dana Kay J. Dagohoy, Jan Richellow D. Daladio, and Aliya Mae B. Viray.-- 
 - Manila:	  Technological University of the Philippines,	  2025. 
 - ix, 117pages:  29cm. 
<br/><br/> Bachelor's thesis<br/> 
<br/><br/>College Of Science.--<br/> 
<br/><br/>Includes bibliographic references and index. 
<br/><br/> This study investigated the potential of biosorption to remove hexavalent chromium [Cr(VI)]<br/>from aqueous solutions using calcium oxide (CaO) nanoparticles synthesized from Tahong<br/>(Asian green mussel) waste shells. CaO nanoparticles were synthesized via two methods: Sol-gel<br/>and Hydrothermal. Characterization using Fourier-Transform Infrared Spectroscopy (FTIR)<br/>confirmed successful decomposition of calcium carbonate to CaO, indicated by the<br/>disappearance of carbonate peaks and the appearance of a strong Ca–O stretching peak at ~554<br/>cm−1. Scanning Electron Microscopy (SEM) revealed that Sol-gel CaO nanoparticles had an<br/>average particle size of approximately 99 nm with porous, aggregated structures ideal for<br/>adsorption. Energy-Dispersive X-ray Spectroscopy (EDX) showed that the synthesized<br/>nanoparticles contained 48.33% calcium and 44.67% oxygen by weight, with minor impurities of<br/>chlorine and sodium; post-adsorption analysis confirmed chromium uptake, with 1.09% Cr<br/>detected. The Sol-gel-derived CaO nanoparticles exhibited a finer morphology and higher<br/>adsorption efficiency, attributed to their increased surface area. Adsorption experiments<br/>examined the effects of various parameters, including adsorbent dosage, initial chromium<br/>concentration, pH, and temperature. Optimal removal efficiency (76.41%) was achieved at pH 5<br/>and 30°C using Sol-gel CaO nanoparticles. Kinetic data fitted best with the pseudo-second-order<br/>model, while equilibrium studies followed the Freundlich isotherm, indicating multilayer<br/>adsorption. This study highlights the efficacy of Tahong-derived CaO nanoparticles as a<br/>sustainable, low-cost biosorbent for heavy metal remediation. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Biosorption<br/>Calcium oxide nanoparticles<br/>Tahong shells
<br/><br/><label>LC Class. No.: </label>BTH RB 37   / A68 2025