Résumé
Objective To develop a remover of formaldehyde in indoor air. Methods Activated carbon was used as the raw materials, potassium hydroxide as the activator. The activated carbon was modified through activation and impregnation. The influence factors for the formaldehyde adsorption property of activated carbons were evaluated, such as the size, activation temperature, activation time and impregnation time. Results The optimum technics conditions for developing the formaldehyde remover and the optimum conditions to absorb formaldehyde were confirmed. The mass adsorption capacity of the adsorbent was 49.6%, the BET surface area was about 1 591 m2/g and the total pore volume was 1.01 cm3/g. Conclusion The mass adsorption capacity of formaldehyde and the BET surface area of the modified activated carbon in the present paper are better than those of unmodified activated carbon.
Résumé
Objective To study the determination of chromium in human hair by spectrophotometry using starch as color agent. Methods The total chromium(Cr)in human hair was oxidized by (NH4?雪2S2O3 into Cr6+,which could oxidize KI to form I-3 in acid medium. I-3 reacted with starch to form a blue colored complex,which revealed the maximum absorption peak at 590 nm. Results The contents of Cr in human hair were 8.46-29.56 ?g/g.The lowest detection limit and linear range were 0.02 and 0.02-1.0 ?g/ml respectively.The coefficient of variation and standard material-added recovery rates were 3.3% and 94.8%-104.5% respectively. Conclusion This methods was rapid,accurate and convenient for the determination of chromium in human hair.