The Experiment Study On Hydroxyapatite Removing Fluorin Of Portal Water

Fluorin is an essential trace element to human,appropriate amount of fluorin is indispensable for maintaining bone and tooth development,but long-term consumption of water with high fluorin would lead to dental fluorosis and skeletal fluorosis or more seriously,will lead to skeletal deformation,pain,joint stiffness,calcified tendons or legs,walking difficulties,even paralysis.Currently,there are still tens of millions of people in our country drinking high-fluorine water,this is a serious threat to human health.In order to explore cost-effective methods and techniques to remove fluorin,this paper chose a newly defluorination—Hydroxyapatite (HAP),and conductedresearches on this defluorination performance, analysised the law of HAP's adsorption of fluoride.This paper only researched the static experiment of HAP removed fluorin.Firstly,determined the solution of initial concentration at 5mg/L,the best fling plus amount was 50mg.Then mainly investigated the influence factors including:temperature,reaction time,pH,the solution of initial concentration,turbidity and so on.Got the conclusion was:when the temperature was 35℃,pH was 5.0,reaction time was 30minutes,the effects was best.The last effluent concentration was below 1mg/L,achieved the《health standard for domestic drinking water》(GB5749-2006)"water quality conventional index and limit value".The relationship between the solution of initial concentration and HAP adsorpted- fluorin was:the more the initial concentration,the low removal rate;the relationship between turbidity and HAP adsorpted- fluorin was:the high the turbidity, first the high removal rate then approached equilibrium.Secondly,according adsorption thermodynamics and adsorption kinetics to research demonstration the mechanism of this non-homogeneous phase solid-liquid reaction.At the different temperature,the experiment of adsorption thermodynamics modified the relationship between temperature and HAP adsorpted- fluorin,and its adsorption isothermal model accordance with Langmuir adsorption isotherm.Through the experiment of adsorption's kinetics three modols,we knew the HAP adsorpted- fluorin was chemical adsorption mainly:the second model.At last,experiments speak volumes for HAP is a high efficiency,economical and no- contamination,it supplied reference basis for lasting research.But the removal rate had a certain restriction,expectation,can take other beneficial measures to improve the HAP's adsorption effects.