Abstract
Hydroxyapatite (HAp)/chitosan composites were prepared by a coprecipitation method, dropping a mixture of chitosan solution and phosphoric acid solution into a calcium hydroxide solution. Using the HAp/chitosan composites prepared, HAp/chitosan hybrid fibers with various HAp contents were prepared by a wet spinning method. X-ray diffraction and scanning electron microscopy analyses revealed that HAp particles were coated onto the surface of the fiber, and the surface roughness increased with increasing the HAp contents in the fiber. In order to evaluate the heavy metal removal characteristics of the HAp/chitosan hybrid fiber, adsorption tests were conducted and the results were compared with those of bare chitosan fibers. The results showed better performance in heavy metal ion removal for the HAp/chitosan hybrid fiber than the chitosan fiber. As the HAp content in the hybrid fiber increased, the removal efficiency of heavy metal ions also increased due to the increase of the specific surface area of the HAp/chitosan hybrid fiber. Adsorption kinetic and isotherm tests revealed that Pb2+and Cd2+adsorption to the hybrid fiber follows pseudo-second-order kinetic and Langmuir-type adsorption, respectively.
Highlights
Heavy metal contamination occurs in aqueous waste streams in many industries, such as metal plating facilities, mining operations, and tanneries [1,2,3]
The (002) crystal face peak near 26∘ due to the HAp particles included in the HAp/chitosan hybrid fiber appeared
While the comparison study between the bare chitosan fiber and the hybrid fiber clearly reveals that the removal performance of the hybrid fiber is significantly better than the bare fiber even at low heavy metal concentration, the difference in heavy metal removal efficiency was minimal among the hybrid fibers
Summary
Heavy metal contamination occurs in aqueous waste streams in many industries, such as metal plating facilities, mining operations, and tanneries [1,2,3]. HAp has an ion-exchange property; it has been reported to be efficient for the removal of various heavy metal ions such as lead, cobalt, nickel, copper, zinc, and cadmium from aqueous solution [8,9,10,11,12]. The powder-type of HAp is unlikely applicable to continuous packed-bed systems, which are commonly used in practical scale, due to high pressure drops by high packing density of powder-type of materials [14]. Both of the aforementioned drawbacks lead to the limitation of their industrial application
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
