The apparent activation energies of the carrier gas through the TMOS, HTMOS, and TEOS derived membranes were 44.3, 49.4, and 71.0 kJ mol-1, respectively. The apparent deposition rates increased with the deposition temperature. The membrane formation processes were compared for each deposition condition and precursor, and the apparent silica deposition rates from the precursors such as tetramethoxysilane (TMOS), hexyltrimethoxysilane (HTMOS), or tetraethoxysilane (TEOS) were investigated by changing the deposition temperature at 400-600 вЊ. Membrane formation processes were evaluated by the decrease of the permeation of the carrier gas derived from pore blocking of the silica deposition. The permeation of the carrier gas used for supplying a silica precursor was quantified during the deposition reaction by using a mass spectrometer. This is the first attempt to provide new insights, such as the decomposition products, membrane selectivity, and precursor reactivity. Take 20ml of the solution under the heavy metal item, and add hydrochloric acid to check according to law (General rule 0822 first law), which shall comply with the regulations (0.0003%).A new evaluation method for preparing silica membranes by counter diffusion chemical vapor deposition (CVD) was proposed. 3G, add 40ml of water and 5ml of hydrochloric acid, slowly heat and boil for 15 minutes, let cool, filter, the filtrate is placed in a 100ml measuring flask, wash the filter with an appropriate amount of water, wash the washing solution into the measuring flask, add water to dilute to the scale, shake well, take 20ml, add 1 drop of phenolphthalein indicator solution, add ammonia solution Dropwise to light red color, add 2M l acetate buffer (pH 3.5) and appropriate amount of water to make 25ml, inspection according to law (General Principles 0821, Law 1), containing heavy metals shall not exceed 30 parts per million. Compared with the control solution made of 0M l, it should not be deeper (0.015%).

2G, add water 25ml, hydrochloric acid 2M l and nitric acid 5 drops, boil for 5 minutes, let cool, filter, wash the filter with a small amount of water, combine the filtrate and wash, add ammonium persulfate 50mg, add water to dilute to 35ml, check according to law (General 0807), and standard iron solution 3. O g, precision weighing, in the lOOtTC ignition for 1 hour, loss of weight should not exceed the dry product weight 8. The Test product l left under the item of loss of drying is taken. Take this product, dry at 145вЊ for 2 hours, weight loss shall not be '5. Compared with the control solution made of 0M l, it should not be deeper (0. Take 10ml of the filtrate under the chloride item, check according to law (General Rule 0 8 0 1 ), and standard potassium sulfate solution 5. Compared with the control solution made of 0M l, it should not be deeper (0.1%). Nitride take 0801g of this product, add water 50ml, heat reflux for 2 hours, cool, add water to make up to 50ml, shake, filter, take the filtrate 10ml, check according to law (general rule), with standard sodium chloride solution 10. Take l g of this product, add water 20 m l, shake, filter, take the filtrate, according to the law (General 0631),p H value should be 5. Take 10g of this product, according to the particle size and particle size distribution determination method inspection, through the seven sieve (125Mm) of the test quantity should not be less than 85%.

Formula of silica