Study On Dry Surface Process Modification Of Quartz Sand And Oil Removal Performance

Oily wastewater is a kind of important refractory organic wastewater, and widely available. Filter method is a common method of oily wastewater treatment. The wettability of filter media plays an important role in the processing of oily waste water filtration efficiency. Commonly used natural quartz sand filter material is a hydrophilic subatance of strong polarity,and has low efficiency of oily wastewater treatment. In order to improve the processing efficiency of oily waste water, it is necessary to improve the quartz sand filter material on the surface of Oil-wet hydrophobic. It shows that using the modifier of the powder particle surface physical and chemical modification can improve the dispersion of particles in other substances. In the early stage of the wet method in this paper based on the study of the modification, the modifier solution sprayed in the modified equipment adequately dispersed particle surface, dry filter, research can be used for basic research and industrial application of quartz sand filter material and dry the surface modification technology. Using the single factor experiment method, choosing common titanate DN101, silane coupling agent KH570 and titanate coupling agent DN101, and silane coupling agent KH550 composite quartz sand filter material of 0.45⁰.90 mm dry surface modification, in addition, using lipophilic hydrophilic ratio?LHR? represent the size of the quartz sand filter material oil-wet hydrophobic. The static adsorption experiment of oily wastewater and dynamic filtration experiment can examine the adsorption performance and oil removal efficiency before and after the modification of quartz sand filter material, meanwile, the relationship between LHR, adsorption capacity, and oil removal efficiency is discussed, which provides the theoretical basis of modified filter material used in wastewater treatment and data support.?1? According to basic equations on wettability of Laplace and Young equation, water and cyclohexane characterize, it's determined to wetting contact angle of oil and water relative to quartz sand filter material by oil phase and water phase, adopting dynamic quality method. The size of the oil-wet hydrophobic filter material is characterized by LHR, and we derived the calculation formula of LHR with dynamic quality method, the LHR of 0.45 0.90 mm natural quartz sand filter material is 1.25.?2? The coupling agent concentration was 1.2%, reaction time was 70 min, reaction temperature was 60 ? which are the optimum condition for DN101 dry surface modification of quartz sand filter material. The coupling agent concentration was 1.0%, coupling agent quality ratio was 1:2, reaction time was 50 min, reaction temperature was 60 ? which are the optimum conditions for DN101 and KH550 compound dry surface modification conditions. The coupling agent concentration was 1.5%, reaction time was 50 min, reaction temperature was 60 ? which are the optimum condition for KH570 dry surface modification of quartz sand filter material. The LHR of quartz sand filter materials, which were modified by DN101, DN101 and KH550 composite, KH570, were 11.1, 7.4, 5.0, respectively. After modified, the water wetting quality to quartz sand filter significantly reduced, cyclohexane wetting quality to quartz sand filter material basically remain unchanged.?3? The results of Scanning Electron Microscopy?SEM?, X-ray Photoelectron Spectroscopy?XPS? and Fourier Transform Infra-Red Spectroscopy?FTIR? show that the coupling agent dry surface modification of quartz sand filter material evenly coated on the surface of a layer of particles, the surface is flat, the edges and corners are reduced, stair fracture is disappeared. Natural quartz sand filter material is composed of Si and O elements in the form of Si O2, the surface Si-OH exists in the form of combined water. Modification of the surface of the quartz sand filter material is C, O, Si element, DN101, DN101 and KH550 composite modified quartz sand filter material surface Ti element. Coupling agent and quartz sand filter material surface hydroxyl condensation reaction and coupling agent molecules grafted in the form of chemical bonds on the surface of quartz sand filter material, form a stable molecule coating.?4? Static adsorption experiment of oily wastewater and dynamic filtration experiment results show that the natural quartz sand filter material after coupling agent dry surface modification that static and dynamic adsorption capacity to filter oil removal efficiency are improved and adsorption capacity growth is greater than the filtering oil removal efficiency increase. In addition LHR value, the adsorption capacity and filter the oil removal efficiency positively correlated relationship between the three. Three numerical DN101 dry surface modification of quartz sand filter material are the highest in several kinds of quartz sand filter material, modified effect is best.?5? The static adsorption experiment results show that the quartz sand filter material of 15.6 mg·L^-1 oily waste water adsorption equilibrium time is about 270 min. The adsorption equilibrium, natural quartz sand filter material, adsorption capacity of 0.244 mg·g^-1, DN101, DN101 and KH550 the adsorption capacity of composite modified quartz sand filter material is 0.418 mg, 0.389 mg·g^-1, less modified quartz sand filter material increased by 71% and 59% respectively. Modified quartz sand filter material of oily waste water adsorption capacity and its largest oil wastewater concentration are linear positive correlation.?6? The results of dynamic filtration experiment show that the quartz sand filter material layer is 90 cm, empty bed filter speed is 4 m·h^-1, filter 17.3 mg, oily waste water of 4h, unmodified oil removal efficiency is about 72.6%, quartz sand filter material DN101, DN101 and KH550 composite modified quartz sand filter material and KH570 oil removal efficiency reached 97.8%, 82.6% and 78.9 %, respectively, when compared with unmodified increased by 34.7%, 13.8% and 34.7% respectively. DN101 dry surface modification of quartz sand filtration experiment results show that the oil removal efficiency and head loss are proportional to the filter material layer height, and filtering filter is inversely proportional to the speed and the initial oil concentration.