Adsorption Of Formaldehyde In Wastewater

Formaldehyde is a high toxic substances,and it is stable at room temperature.Because of its wide source,low hazard threshold,and volatile,formaldehyde poses a threat to human health and the survival of microorganisms in the water.Therefore,the management of formaldehyde pollution has been one of the hot spots of scholars.At present,there has fenton method,catalytic oxidation method,biological method,blowing method and adsorption method and so on to dispose formaldehyde wastewater.Among them,the adsorption method is widely used because of its easy operation,good effect,low cost and so on.As one of the most commonly used adsorbents,activated carbon is restricted in treating wastewater due to its expensive price,so the search for new adsorption material that has low cost and good adsorption performance has important environmental and economic significance.Sepiolite and blue-coke are both porous substances,the use of its adsorption performance has been reported,and the cost of these two substances is only one-tenth of the activated carbon,in this paper,sepiolite and blue-coke were modified respectively,and the adsorption effect of formaldehyde on wastewater of these was studied.Through the analysis of SEM,BET,TG and XRD,it is found that the internal fouling of the blue-coke and sepiolite is cleaned,the pore is opened and the specific surface area is greatly improved after activation.The structure of the adsorbent is more stable with the metal oxide loaded and and the iron oxide is mainly supported on the surface of the adsorbent.The effects of various factors on the adsorption performance of adsorbent were investigated by single factor experiment.The results showed that the removal rate of formaldehyde was increased with the increase of pH,oscillation rate and dosage of adsorbent,and decreased with the increase of temperature.In the rate of 180r/min,PH is 3,dosage of modified fine blue-coke is 10g/L,the adsorption capacity achieves 1.91mg/g at 298 K.The adsorption capacity of modified sepiolite on the formaldehyde in the solution increased with the increase of the initial concentration of the solution,and decreased with the increase of the dosage of the adsorbent.,the adsorption capacity achieves 0.54mg/g at optimal conditionThe adsorption properties of modified blue-coke on formaldehyde were better than that of sepiolite,and it is almost the same as carbon.Therefore,the modified blue-coke was used as the research object.Through the thermodynamics and kinetics of formaldehyde adsorption,the adsorption mechanism was discussed.