| Volatile organic compounds(VOCs) pose a threat to atmospheric environment and human health. Using molecular sieve as adsorbent, an adsorption type of honeycomb rotary wheel system for the removal of big air volume, low concentration organic waste gas, has the advantages such as high efficiency, continuous operation and low energy consumption, so it is widely used in industrial exhaust processing. In this system, the rotary wheel(Monolithic adsorbent) is the core unit, which is a key factor to determine system performance for the purification of the organic waste gas. Based on this, this paper deeply discusses the preparation and performance of monolithic adsorbent for the purification of VOCs.First, it was discussed about the preparation of ceramic corrugated paper, honeycomb monolith and molecular sieve corrugated paper. The influences of wetting agents(SDS,OP-10 and co-436) on the wettability of ceramic corrugated paper were also investigated. The effect of drying process(hot air, microwave) on the colloidal silica distribution onto the ceramic corrugated paper was studied. The effect of the molecular sieve mass fraction on the coating mass of ceramic corrugated paper was analyzed.Experimental results found that the wetting agent could obviously improve the wetting performance of silicon sol on ceramic corrugated paper. Specifically, the modification effect of nonionic surfactant alkyl phenol polyoxyethylene ether(OP-10) was the most significant. Compared with blank, its wetting time changed from more than 24 h to 6.73 s, and the contact angle of modification silicon sol decreased from 35.45°to 23.08 °. SEM photograph showed that, compared with hot air drying, microwave drying made the silicon sol distribution on corrugated paper more uniform. With the increase of the molecular sieve mass fraction, the coating mass of ceramic corrugated paper showed up, when the mass fraction was 23.08%, the increasing rate changed slowly, when further increasing to33.33%, the accompanied phenomenons of off powder and plugging hole on ceramic corrugated paper took place.Secondly, after the primaries, the ceramic corrugated adsorption paper separately made by domestic molecular sieve(DM) and import molecular sieve(IMa or IMb) as adsorbent, the typical VOCs such as polar solvent methylene chloride(CH2Cl2) and nonpolar solvent benzene(C6H6) as adsorbate, the influence of temperature, adsorbate concentration and inlet air flow rate on the adsorption performance of ceramic corrugated adsorption paper was respectively investigated by dynamic adsorption. Results showed that the removal effect of VOCs on adsorption paper was obvious. Among them, the adsorption performance of IMa paper was the optimal, especially to the adsorption of benzene. When methylene chloride as adsorbate, the influence of temperature and adsorbate concentration was the most obvious for IMa paper and the one of the air flow rate was conspicuous for IMb paper. With the increase of the molecular sieve mass fraction, the breakthrough times and the adsorbing capacity of both CH2Cl2 and C6H6 on all the adsorption papers increased. The decrease of breakthrough time and adsorbing capacity for CH2Cl2 on IMa adsorption paper may be related to a large pore volume and blocking pore channel, which resulting in the increase of mass transfer resistance, it also was correlate to a greater adsorption heat for CH2Cl2 on IMa to be difficult to dissipate.Finally, toluene(C7H8) as adsorbate, a preliminary study about the adsorption performance of DM honeycomb ceramic monolith was carried out, the test results showed a excellent breakthrough time(80min) and adsorption capacity(1.332×10-2 g?g-1). |
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