活性炭碘吸附值的檢測方法及要點

1、歡迎共閱活性炭碘吸附值的檢測方法及要點原理一定量的試樣與碘液充分振蕩吸附后，經(jīng)過濾，取濾液，用0.1mol/L硫代硫酸鈉滴定濾液中殘留的碘量。以剩余碘濃度0.02mol/L時每克炭吸附的碘量（以毫克計）定為碘值。儀器天平，感量0.1mg;I1電熱恒溫箱，115±5C;.一、.«I11III:攪拌式粉碎機；.?.I,.、j,二1八III振蕩器，頻率240275次/min;標準篩，篩孔71微米（250目，篩孔66微米）。試齊I1） 1mol/L碘標準溶液（GB601）濃度控制0.1±0.002mol/L,用硫代硫酸鈉比c"!1較法標定。2） 0.1mol/L

2、硫代硫酸鈉標準溶液（GB601）3） 0.5g/100mL淀粉指示劑：稱0.5g可溶性淀粉，加水10mL,在攪拌下加人90mL沸水中，再微沸2min,冷卻后取上清液使用，此溶液當天配制。4） （1+9鹿酸溶液。樣品預處理1）除濕：對于濕活性炭，用150士5c干燥1小時再粉碎；2）粉碎：取1015g樣品粉碎1min（粉碎時用毛巾或塑料袋罩住粉碎機，3min后飛揚粉塵較少時再開蓋）；3）過篩：用250目標準篩，篩粉碎的樣品，充分搖動；4）干燥：取510產(chǎn)71微米的粉碎樣品于干燥稱量皿中，于150±5C電熱恒溫箱中干燥至恒重（一般3h足夠），取出放干燥器中冷卻至室溫備用。檢測步驟1）用減量

3、法稱取經(jīng)粉碎至w71微米且干燥的試樣約0.5g例準至0.4mg）于干燥的250mL碘量瓶中，記錄稱取的試樣量；IrI_2）準確加入鹽酸10.0mL,輕微搖動，使試樣濕潤，放在電爐上加熱至沸，提離電爐，保持微沸30±2S,放入自來水浴中冷卻至室溫；3）力口0.1mol/L的碘標準溶液50.0mL,塞好瓶蓋，立即在振蕩機上以240275ItII，“l(fā)l./,.1/次/min的振頻振蕩15min;、i/八jI-7，.了!JiI4）用直徑15cm的單層快速濾紙迅速過濾，用玻璃片蓋住過濾漏斗，前1075mL棄去不要，收集后面的濾液；5）吸取10.0mL濾液放人已加100ML蒸儲水的碘量瓶中，用

4、0.1硫代硫酸鈉標準溶液滴定，在溶液呈淡黃色時，加2mL淀粉指示劑，繼續(xù)滴定至溶液變成無色，記錄消耗的硫代硫酸鈉體積（mL）。結(jié)果計算1）計算剩余濾液濃度=C2*V2/102）據(jù)剩余濃度查附表得出校正系數(shù)D3）計算碘值，mg/g5（10G-1.2（GV2）*127A=*D式中:A試樣的碘吸附值，mg/gCi碘液濃度，mol/LC2硫代硫酸鈉標準溶液濃度，mol/LV2硫代硫酸鈉溶液消耗量，mLM試樣質(zhì)量，g127碘（1/212）摩爾質(zhì)量，g/molD一校正系數(shù)。U,I13精確度:碘值在6001450mg/g時，兩個平行樣之差w5.6%。檢測要點1）因為活性炭顆粒的大小、與碘振搖的時間、頻率對活

5、性炭吸附碘的能力有ItIIbI;7/影響。嚴格選用標準篩和振搖時間、頻率。要求活性炭孔徑w71微米時，可選f-«.''»I,”"用220目或250目的標準篩；2）樣品應干燥。因為活性炭吸水能力極強，在目測正常情況下，水分可高達X.120%嚴重影響稱量的準確性；3）用減量法稱量活性炭。因為活性炭能快速吸水，暴露時間長會影響稱量的準確性；4）因碘易揮發(fā)，移液管加碘液時沿碘量瓶下壁放出，選用配套的碘量瓶，在振搖時密封好，減少碘的損失；5）濾紙吸附碘，特別是初濾的10mL,可達7.7%,后面的濾液碘損失率逐漸減少至1.8%,故選用快速濾紙，初濾的1015m

6、L濾液不用。6）據(jù)試樣碘值不同，調(diào)整試樣稱量范圍，控制滴定量在0.83.3mL確保剩余濾液濃度在校正因子表內(nèi)，查得到校正因子。碘值越低，稱量越多。附表1碘值試驗的校正因子D剩余濃度0.00000.000I；0.00020.00030.00040.00050.00060.000710.00080.00090.00801.16251.16131.1601.15751.15501.15331.15151.150011.14751.14630.00901.14381.14251.14001.13751.13631.13501.13251.1300(1.12881.12750.01001.12501.1

7、2381.12251.12131.12001.11751.11631.11501.11381.11130.01001.11001.10881.10751.10631.10381.10251.10001.0988|1.09751.09630.01201.09501.09381.09251.09001.08881.08751.08631.08501.08381.08250.01301.08001.07881.07751.07631.07501.07381.07251.0713.1.07001.06880.01401.06751.06631.06501.06251.06131.06001.05831

8、.057511.05631.05500.01501.05381.05251.05131.05001.04881.04751.04631.04501.04381.04250.01601.04131.04001.03881.03751.03751.03631.03501.0333.1.03251.03130.01701.03001.02881.02751.02631.02501.02451.02381.02251.02081.02000.01801.02001.01881.01751.01631.01501.01441.01381.01251.01251.01130.01901.01001.008

9、81.00751.00751.00631.00501.00501.0038.1.00251.00250.02001.00131.00001.00000.99880.99750.99750.99630.995010.99500.99380.02100.99380.99250.99250.99130.99000.99000.98880.98750.98750.98630.02200.98630.98500.98500.98380.98250.98250.98130.9813.0.98000.97880.02300.97880.97750.97750.97630.97630.97500.97500.

10、973810.97380.97250.02400.97250.97080.97000.97000.96880.96880.96750.96750.96630.96630.02500.96500.96500.96380.96380.96250.96250.96130.9613.0.96060.96000.02600.96000.95880.95880.95750.95750.95630.95630.950010.95500.95380.02700.95380.9525.0.95250.95190.95130.95130.95060.950010.95000.94880.02800.94880.94750.94750.94630.94630.94630.94500.94500.94380.94380.02900.94250.94250.84250.84130.94130.94000.94000.939410.93880.93880.03000.93750.93750.93750.93630.93630.93630.93630.9350,0.93500.93460.03