Treatment Of Volatile Organic Compounds In Pulp Mills And Air Cleaning By Adsorption

Methanol is one of the main alcohol pollutants generated in the pulping process. A technique of headspace gas chromatographic (HS-GC) for the determination of methanol absorbed on natural clinoptilolite (NC) particles was firstly established. In this method, a very small quality (?0.200 g) of solid sample is introduced into a headspace sample vial (20 mL) and the data indicated that a near-complete mass transfer of methanol from the solid to the vapor phase (headspace) was achieved within 30 min at 80?. The methanol in the headspace of the vial was then measured by GC. The present method has excellent precision (RSD < 3.09%) and accuracy (recovery > 92%) for the quantification of methanol absorbed on NC particles.The waste gas of pulping mill was simulated by the atmosphere volatilized from contaminated condensate, then, the feasibility about treatment of methanol in waste gas of pulp mills by adsorption has been explored,and zeolite molecular sieve,natural zeolite,residues of pulp mills (such as sawdust and bagasse pith) were used as adsorbents to investigate the adsorption of methanol in this work. Influencing factor of temperature, time and methanol concentration on adsorption of methanol on natural ZSM-5 hydrophobic molecular sieve, 5A molecular sieve and clinoptilolite were discussed, then, the adsorbed performance of sawdust and bagasse pith in different moisture content was investigated.The results indicate that ZSM-5 hydrophobic molecular sieve has the best absorption property and 5A molecular sieve performs better in terms of methanol absorption,compared to natural clinoptilolite. The three inorganic material's adsorption quantity at equilibrium increased with lower temperature and higher methanol concentration, and the adsorption equilibrium time decreased with the increase of temperature. The adsorption quantity at equilibrium on ZSM-5 hydrophobic molecular sieve, 5A molecular sieve and natural clinoptilolite at 40? were 13.72 mg/g, 4.66 mg/g and 2.67 mg/g, respectively.Moisture content affects the adsorptive performance of the residues. The equilibrium time and adsorption capacity increase with the rise of moisture content in laboratory conditions.It took pine sawdust (moisture content was 59.89%), eucalyptus sawdust (55.29%) and bagasse pith (54.82%) 12h, 10h and 5h to reach adsorption equilibrium and their saturated methanol extent of adsorption were 16.30 mg/g, 12.84 mg/g, 13.56 mg/g, respectively.Residues (i.e. sawdust, bagasse pith) can be used to adsorb waste gas generated during pulping before being burnt in the boiler.Method for determination of formaldehyde adsorbed on adsorbents was optimized firstly, then, performance of several adsorbents (such as acticarbon and handsheet of pulp)in the adsorption of formaldehyde and influence of pretreatments did on pulp were investigated. And saturated formaldehyde extent of adsorption for acticarbon, hand sheet made from unbleached slab caustic soda-anthraquinone pulp, bleached kraft hardtwood pulp, bleached kraft softwood pulp were 1.82 mg/g, 0.137 mg/g, 0.133 mg/g and 0.124 mg/g,respectively.