Experimental Study On Purification Of Rainwater By Mineral Materials

Rainwater is an important component of fresh water resources in urban. It is an important way of the solution to water supply and demand contradiction. However, the rain washing the air and scour the ground, containing large quantities of pollutants, led to the indirect serious pollution on soil, groundwater resources. Therefore, to purify the rainwater of city is one of the important measures to alleviate urban water shortage. Environmental mineral material has larger surface area and large number of activity points, it has strong adsorption capacity, it can happen chemical adsorption and physical adsorption with the adsorbate, it has effective adsorption of heavy metal ions, organic pollutants and inorganic pollutants in aqueous solution.In this paper, I use fly ash, diatomite, bentonite, zeolite materials as a pilot test of the decontamination of rain water, the rain water purification mainly for the CODcr, BOD, SS and the removal of heavy metal pollution. During the experiment, by changing the reaction time, materials, dosage, PH value of solution and reaction temperature to study the removal efficiency of heavy metal ions, CODcr, NH4-N and turbidity in rainwater by purification materials; and analysis the removal efficiency of heavy metal ions, CODcr, NH4-N and turbidity in rainwater by activated modified purification material.The experiment results show that:the selected environmental mineral materials has efficiency of removal on the Cu+, Fe+, Zn2+, the removal rate of Fe3+is maximum, the removal rate of fly ash, diatomite, bentonite, zeolite respectively can reach 99.73%, 72.2%,96.93%,94.85%.According to the conditions of the experiment, the amount of purified material, solution PH value and the initial concentration of the solution have greater impact on purification efficiency. In the purification material, the removal of CODcr in rainwater by Bentonite is 42.86%; the removal of ammonia by zeolites is 29.37%; the removal of turbidity by fly ash is 52.23%.After active ignition modified, the purify efficiency of purification material has a significant increase, When the calcination temperature is 400℃the removal of Cu2+, Fe3+, Zn2+ in solution and rainwater CODcr, ammonia nitrogen, turbidity is best. After modified, the removal efficiency of rainwater CODcr by fly ash increased to 63.4%, the removal rate of nitrogen by zeolite increased to 51.53%, removal rate of turbidity by fly ash increased to 69.5%.In this paper, I studied the adsorption mechanism of heavy metal ions by purification materials, the environment mineral material has a good surface and interfacial properties and pore structure, the adsorption mechanism of heavy metal ions, including the purification and adsorption of heavy metal material and the surface reaction.