Indoor Air The Formaldehyde Pollution Monitoring And Removal Methods Research

Residence fitment craze aggravates the indoor air pollution and induces serious human health problems. Formaldehyde is one of the main important indoor pollutants.which is been deeply concerned more and more. Researchers in and out have being studied a lot on the prevention and cure of formaldehyde..The paper bring forward self opinion of formaldehyde monitoring and control on the basis of those research: Monitoring should firstly ensure that results are accurate and credible. Pollution control should pay fully attention to stable purification and the feasibility of marketing. Going on this premise, we can search simple, fast, safe, economic methods for formaldehyde monitoring and control. The study includes the following parts: 1 , Monitoring methods improving(1)Based on the phenol reagent spectrophotometry , we researched into the whole process of formaldehyde determination, studied the stability of the main reagents, improved on the sampling method and chromogenic reaction conditions. Through the experiment, we know:the absorbing liquid confected by phenol reagent can be kept at room temperature, the service life can be extended to five days.; When we use the ammonium ferric sulfate to confect color reagent, add 10mL0.1mol/L hydrochloric acid is better, and time for the color reagent usage should not exceed one week. Formaldehyde solution is Relatively stable and can be used for two months when kept in refrigerator.(2)We chose the optimal experimental conditions: The absorbance wave length: 630 nm indicator consumption: 10 g / L ammonium ferric sulfate pH: optimal value is around 2.86 temperature: 20 ℃ — 30 ℃reaction time :better to control it between 15—20 min(3)We shortened the time spent on analysis. It is proved that Sampling time can be fix on 20 minutes instead of 45 minutes.After the optimization, the detection limit of formaldehyde can be reduced to 0.0103μg/mL ,the method become more accurate, simple, and rapid, and better suitable for monitor of indoor air pollution. 2, Study of pollution controlFormaldehyde in indoor air can be absorbed by the solution absorbtion via chemical reaction under normal temperature and pressure. This method have no use for ultraviolet radiation assistant, and the liquid absorbent is easier to replace than solid adsorbent. But right now study on this aubject is not sufficient. We used formaldehyde solution of different concentration to simulate thickness of high, middle, low indoor formaldehyde condition, and test the possibility for those reagents to reaction with formaldehyde under normal temperature. The reagents are as follows: abio-ammonium salt, sodium sulfite (bisulphite), potassium permanganate, sodium peroxydisulfate, Feilin reagent, tea and so on, those experiments show:(1) At normal temperature and pressure, 1L water can assimilate about 1.5 mg of formaldehyde,, the absorb capacities is very low, so it is unpractical to absorb formaldehyde by water only.(2) Abio-ammonium salt such as ammonium sulphate, ammonium chloride, ammonium molybdate etc. can react with high and medium thickness formaldehyde quickly at normal temperature ,but the reaction condition with low thickness formaldehyde is not ideal(3) Sodium sulfite (bisulphite) can efficiently assimilate formaldehyde at any thickness, but the process of assimilate may release SO₂ gas, which can induce secondary pollution, and the reaction is reversible. So we don't suggest this method apply to the indoor air decontaminate.(4) Sodium glutamate doesn't react with formaldehyde at normal situation.(5) Reaction between potassium permanganate and formaldehyde is prompt, the absorb ability is:acidic potassium permanganate solution> basic solution > neuter solution, at the basic condition, adding sodium carbonate is better than adding sodium hydroxide; sodium supersulphate can not react with formaldehyde ant normal temperature (6) Fehling reagent can react with formaldehyde when the solution is heated, but at room temperature the velocity of the reaction is very slow.(7) Tea can efficiently absorb formaldehyde at room temperature, this method is suitable for indoor air decontaminate.