Mukugadzira uye hupenyu, silica gel inogona kushandiswa kuomesa N2, mhepo, hydrogen, gasi rechisikigo [1] zvichingodaro. Maererano neasidhi uye alkali, desiccant inogona kugoverwa kuva: acid desiccant, alkaline desiccant uye neutral desiccant [2]. Silica gel inoratidzika seine neutral dryer inoita seyakaoma NH3, HCl, SO2, etc. Zvisinei, kubva panheyo yekuona, silica gel inoumbwa ne-three-dimensional intermolecular dehydration ye orthosilicic acid molecules, muviri mukuru iSiO2, uye nzvimbo yacho yakapfuma mumapoka ehydroxyl (ona Mufananidzo 1). Chikonzero nei silica gel inogona kutora mvura ndechekuti iyo silicon hydroxyl boka riri pamusoro pe silica gel rinogona kuumba intermolecular hydrogen zvisungo nemamorekuru emvura, saka inokwanisa kushambadza mvura nekudaro kuita basa rekuomesa. Iko-inoshandura silica gel ine cobalt ions, uye mushure meiyo adsorption mvura yasvika pakuzara, iyo cobalt ions mu-ruvara-inoshandura silica gel inova hydrated cobalt ions, kuitira kuti yebhuruu silica gel inova pink. Mushure mekupisa iyo pink silica gel pa200 ℃ kwenguva yakati rebei, iyo hydrogen bond pakati pesilica gel nemamorekuru emvura inotyoka, uye iyo yakasvibiswa silica gel inoshanduka bhuruu zvakare, kuti dhizaini yechimiro chesilica acid uye silica gel inogona. kushandiswa zvakare sezvinoratidzwa mumufananidzo 1. Saka, sezvo pamusoro pesilica gel yakafuma mumapoka ehydroxyl, pamusoro pesilica gel inogonawo kuumba intermolecular hydrogen bonds neNH3 neHCl, nezvimwewo, uye panogona kunge pasina nzira yekuita se desiccant yeNH3 neHCl, uye hapana mushumo wakakodzera mumabhuku aripo. Saka zvakaguma nei? Nyaya iyi yakaita tsvakiridzo yekuedza inotevera.
FIG. 1 Chimiro dhizaini ye ortho-silicic acid uye silica gel
2 Kuedza Chikamu
2.1 Kuongorora kwehuwandu hwekushandiswa kwesilica gel desiccant - Ammonia Kutanga, iyo yakasvibiswa silica gel yakaiswa mumvura yakasvibiswa uye yakaisa ammonia mvura maererano. Discolored silica gel inoshanduka pink mumvura yakasvibiswa; Mune yakanyungudutswa ammonia, iyo-inoshandura-ruvara silicone inotanga kutsvuka uye zvishoma nezvishoma ichichinja bhuruu. Izvi zvinoratidza kuti silica gel inogona kutora NH3 kana NH3 ·H2 O muammonia. Sezvinoratidzwa muMufananidzo 2, calcium hydroxide yakasimba uye ammonium chloride zvakasanganiswa zvakaenzana uye zvinopisa muchubhu yekuedza. Iyo gasi inoguma inobviswa nealkali lime uyezve ne silica gel. Ruvara rwesilica gel padhuze negwara rekupinda rinova rerureruka (ruvara rwechikumbiro cheiyo silica gel desiccant muMufananidzo 2 inoongororwa - ammonia 73, chikamu chechisere cha2023 chakafanana nemuvara wesilica gel yakanyudzwa. mumvura yakadzika yeammonia), uye iyo pH test bepa haina shanduko iri pachena. Izvi zvinoratidza kuti NH3 yakagadzirwa haisati yasvika pabepa rekuongorora pH, uye yakanyatso kushambadzwa. Mushure menguva yakati, misa kupisa, tora chikamu chidiki chesilica gel bhora, uise mumvura yakanyungudutswa, wedzera phenolphthalein kumvura, mhinduro inoshanduka tsvuku, zvichiratidza kuti silica gel ine simba adsorption. NH3, mushure mekunge mvura yakasvibiswa yakavharwa, NH3 inopinda mumvura yakasvibiswa, mhinduro ndeye alkaline. Naizvozvo, nekuti silica gel ine yakasimba adsorption yeNH3, iyo silicone yekuomesa mumiriri haigone kuomesa NH3.
FIG. 2 Kuongorora kwechikamu chekushandiswa kwesilica gel desiccant - ammonia
2.2 Kuongorora kwehuwandu hwekushandiswa kwesilica gel desiccant - hydrogen chloride inotanga kupisa NaCl solids nedoro rambi murazvo kubvisa mvura yakanyorova muzvikamu zvakasimba. Mushure mekunge sampu yatonhodzwa, yakanyungudutswa sulfuric acid inowedzerwa kuNaCl solids kuti ibve yaburitsa huwandu hukuru hwemabhuru. Iyo gasi inogadzirwa inopfuudzwa mu spherical drying chubhu ine silica gel, uye rakanyorova pH test bepa rinoiswa kumagumo kwechubhu yekuomesa. Iyo silica gel kumucheto kumberi inoshandura girini yakapfava, uye nyoro pH test bepa harina shanduko iri pachena (ona Mufananidzo 3). Izvi zvinoratidza kuti gasi rakagadzirwa reHCl rinonyatso kushambadzwa nesilica gel uye haritizire mumhepo.
Mufananidzo 3 Tsvagiridzo pachiyero chekushandiswa kwesilica gel desiccant - hydrogen chloride
Iyo silica gel yakashambadza HCl uye yakashanduka yakasvibira yakaiswa muyedzo chubhu. Isa iyo itsva yebhuruu silica gel muyedzo chubhu, wedzera concentrated hydrochloric acid, silica gel zvakare inova yakareruka yegirinhi ruvara, iwo maviri mavara akafanana. Izvi zvinoratidza silica gel gasi mune spherical drying chubhu.
2.3 Kuongorora kushandiswa kwechiyero chesilica gel desiccant - sulfur dioxide Mixed concentrated sulfuric acid ne sodium thiosulfate yakasimba (ona Mufananidzo 4), NA2s2 O3 + H2 SO4 ==Na2 SO4 +SO2 ↑+S↓+H2 O; Iyo gasi inogadzirwa inopfuudzwa kuburikidza nekuomesa chubhu ine discolored silica gel, iyo yakasvibiswa silica gel inova yakareruka yebhuruu-girinhi, uye yebhuruu litmus bepa pakupera kwebepa rekunyorova rebvunzo harishanduke zvakanyanya, zvichiratidza kuti iyo yakagadzirwa SO2 gasi ine. yakanyatso kushambadzirwa ne silica gel bhora uye haigone kutiza.
FIG. 4 Kuongorora kwehuwandu hwekushandiswa kwesilica gel desiccant - sulfur dioxide
Bvisa chikamu chesilica gel bhora uye uise mumvura yakasvibiswa. Mushure mekuenzanisa kwakakwana, tora shoma shoma remvura papepa re blue litmus. Pepa rekuyedza harichinji zvakanyanya, zvichiratidza kuti mvura yakasvibiswa haina kukwana kuti desorbed SO2 kubva silica gel. Tora chikamu chidiki che silica gel bhora wopisa mu test tube. Isa bepa reblue litmus rakanyorova pamuromo wechubhu yebvunzo. Bepa reblue litmus rinoshanduka dzvuku, zvichiratidza kuti kupisa kunoita kuti SO2 gasi ribviswe kubva musilica gel bhora, zvichiita kuti bepa re litmus riite tsvuku. Zviyedzo zviri pamusoro zvinoratidza kuti silica gel inewo yakasimba adsorption mhedzisiro paSO2 kana H2 SO3, uye haigone kushandiswa pakuomesa SO2 gasi.
2.4 Kuongorora kwechikamu chekushandiswa kwesilica gel desiccant - Carbon dioxide
Sezvinoratidzwa mumufananidzo 5, sodium bicarbonate solution inodonha phenolphthalein inoita seyakatsvuka. Iyo sodium bicarbonate solid inodziiswa uye musanganiswa wegasi unobva wapfuura nemuchubhu yekuomesa ine akaomeswa silica gel spheres. Iyo silica gel haichinji zvakanyanya uye sodium bicarbonate inodonha ine phenolphthalein inoshambadza iyo HCl. Iyo cobalt ion mune yakasvibiswa silica gel inoumba yakasvibira mhinduro ine Cl- uye zvishoma nezvishoma inova isina ruvara, zvichiratidza kuti kune CO2 gasi yakaoma pamagumo espherical drying chubhu. Iyo yakasvibira-yakasvibira silica gel inoiswa mumvura yakasvibiswa, uye yakasvibiswa silica gel zvishoma nezvishoma inoshanduka kuita yero, zvichiratidza kuti HCl yakashambadzirwa nesilica gel yakanyungudutswa mumvura. Chikamu chidiki chemushonga wemvura wepamusoro wakawedzerwa kune sirivheri nitrate solution acidified nenitric acid kuti iite white precipitate. Iyo diki yeaqueous solution inodonhedzwa pahupamhi hwepH test paper, uye bepa rekuyedza rinoshanduka dzvuku, zvichiratidza kuti mhinduro ine acidic. Zviyedzo zviri pamusoro zvinoratidza kuti silica gel ine adsorption yakasimba kune HCl gasi. HCl inzvimbo yakasimba yepolar molecule, uye boka rehydroxyl riri pamusoro pesilica gel rinewo polarity yakasimba, uye maviri acho anogona kuumba intermolecular hydrogen bonds kana kuti ane simba rakanyanya dipole dipole kupindirana, zvichiita kuti pave neine simba rakati intermolecular simba pakati pechiso chesilica. gel neHCl mamorekuru, saka silica gel ine adsorption yakasimba yeHCl. Naizvozvo, silicone drying agent haigone kushandiswa kuomesa HCl kupukunyuka, kureva kuti, silica gel haina adsorb CO2 kana kuti zvishoma adsorb CO2.
FIG. 5 Kuongorora kwehuwandu hwekushandiswa kwesilica gel desiccant - carbon dioxide
Kuti uratidze kushambadza kwesilica gel kune kabhoni dioxide gasi, zvinotevera zviedzo zvinoenderera mberi. Iyo silica gel bhora muspherical drying chubhu yakabviswa, uye chikamu chakakamurwa kuita sodium bicarbonate solution inodonha phenolphthalein. Iyo sodium bicarbonate solution yakasvibiswa. Izvi zvinoratidza kuti silica gel inoshambadza carbon dioxide, uye mushure mekunyungudika mumvura, carbon dioxide desorbs mu sodium bicarbonate solution, zvichiita kuti sodium bicarbonate solution ipere. Chikamu chakasara chesilicone bhora chinopisa muchubhu yakaoma yekuedza, uye gasi rinoguma rinopfuudzwa mumhinduro ye sodium bicarbonate inodonha ne phenolphthalein. Nenguva isipi, sodium bicarbonate solution inoshanduka kubva pakutsvuka kusvika kusisina ruvara. Izvi zvinoratidza zvakare kuti silica gel ichine adsorption kugona kwe CO2 gasi. Zvisinei, simba rekushambadza resilica gel pa CO2 iduku zvikuru kupfuura yeHCl, NH3 uye SO2, uye carbon dioxide inogona kungoshandiswa zvishoma panguva yekuedza muFigure 5. Chikonzero nei silica gel inogona zvishoma adsorb CO2 inogona kuva kuti silica gel uye CO2 zvinoumba intermolecular hydrogen zvisungo Si - OH… O =C. Nekuti iyo yepakati kabhoni atomu yeCO2 isp hybrid, uye iyo silica atomu musilica gel ndeye sp3 hybrid, iyo linear CO2 molecule haishande zvakanaka nepamusoro pesilica gel, zvichiita kuti simba rekushambadza resilica gel pacarbon dioxide riwedzere. diki.
3.Kuenzanisa pakati pekunyungudika kwemagasi mana ari mumvura uye adsorption status pamusoro pesilica gel Kubva pamigumisiro yekuedza iri pamusoro, inogona kuonekwa kuti silica gel ine simba rakasimba rekudsorption yeammonia, hydrogen chloride uye sulfur dioxide, asi. diki adsorption simba recarbon dioxide (ona Tafura 1). Izvi zvakafanana nekunyungudika kwemagasi mana ari mumvura. Izvi zvinogona kunge zviri nekuti mamorekuru emvura ane hydroxy-OH, uye pamusoro pesilica gel zvakare yakapfuma muhydroxyl, saka kunyungudika kweaya magasi mana ari mumvura kwakada kufanana nekushambadza kwayo pamusoro pesilica gel. Pakati pemagasi matatu eammonia gasi, hydrogen chloride uye sulfur dioxide, sulfur dioxide ine diki kunyungudika mumvura, asi mushure mekushambadzwa nesilica gel, ndiyo yakanyanya kuoma kudhiza pakati pemagasi matatu. Mushure meiyo silica gel adsorbs ammonia uye hydrogen chloride, inogona kucheneswa nemvura inonyungudutsa. Mushure mekunge sulfur dioxide gasi yakashambadzirwa nesilica gel, zvakaoma kunyura nemvura, uye inofanira kupisa kusvika pakuparara kubva pamusoro pesilica gel. Naizvozvo, kushambadza kwemagasi mana pamusoro pesilica gel kunofanirwa kuverengerwa.
4 Theoretical calculation yekudyidzana pakati pesilica gel nemagasi mana inoratidzwa mu quantumization ORCA software [4] pasi peiyo density functional theory (DFT). Iyo DFT D/B3LYP/Def2 TZVP nzira yakashandiswa kuverenga nzira dzekudyidzana uye simba pakati pemagasi akasiyana uye silica gel. Kuti kuverenga kuve nyore, silica gel solids inomiririrwa ne tetrameric orthosilicic acid mamorekuru. Mhedzisiro yekuverenga inoratidza kuti H2 O, NH3 neHCl zvese zvinogona kuumba mahydrogen bond neboka rehydroxyl pamusoro pesilica gel (ona Mufananidzo 6a ~ c). Vane simba rakasimba rekubatanidza pane silica gel pamusoro (ona Tafura 2) uye inoshambadza nyore nyore pane silica gel pamusoro. Sezvo simba rekusunga reNH3 neHCl rakafanana nereH2 O, kugezwa kwemvura kunogona kutungamirira mukuparara kweaya mamorekuru maviri egasi. Kune iyo SO2 molecule, simba rayo rinosunga ingori -17.47 kJ/mol, iyo idiki zvakanyanya kupfuura mamorekuru matatu ari pamusoro. Nekudaro, kuyedza kwakasimbisa kuti SO2 gasi inoshambadzwa zviri nyore pasilica gel, uye kunyange kugeza haigone kuibvisa, uye kupisa chete kunogona kuita kuti SO2 ibude kubva pamusoro pesilica gel. Naizvozvo, takafungidzira kuti SO2 ingangobatana neH2 O pamusoro pesilica gel kuti igadzire H2 SO3 zvikamu. Mufananidzo 6e unoratidza kuti H2 SO3 molecule inoumba matatu ehydrogen bond ane hydroxyl uye maatomu eokisijeni pamusoro pesilica gel panguva imwe chete, uye simba rekubatanidza rinosvika -76.63 kJ / mol, inotsanangura chikonzero nei SO2 yadsorbed pa. iyo silica gel inonetsa kunzvenga nemvura. Isiri-polar CO2 ine iyo isina kusimba yekusunga kugona ne silica gel, uye inogona kungo shongedzwa zvishoma ne silica gel. Kunyange zvazvo simba rinosunga reH2 CO3 uye silica gel yakasvikawo -65.65 kJ / mol, chiyero chekushandura CO2 kusvika kuH2 CO3 chakanga chisina kukwirira, saka chiyero chekushambadza che CO2 chakaderedzwawo. Inogona kuonekwa kubva kune data iri pamusoro apa kuti polarity ye molecule yegesi haisi iyo chete chirevo chekutonga kana inogona kudsorbed ne silica gel, uye iyo hydrogen bond yakaumbwa ne silica gel pamusoro ndicho chikonzero chikuru chekushambadza kwayo kwakagadzikana.
Kuumbwa kwesilica gel ndeyeSiO2 ·nH2 O, nzvimbo yakakura yesilica gel uye boka rakapfuma rehydroxyl riri pamusoro rinogadzira silica gel inogona kushandiswa seine-non-chepfu dryer nekushanda kwakanaka, uye inoshandiswa zvakanyanya mukugadzira uye hupenyu. . Mupepa iri, inosimbiswa kubva kune maviri maficha ekuyedza uye theoretical calculation kuti silica gel inogona adsorb NH3, HCl, SO2, CO2 nemamwe magasi kuburikidza neintermolecular hydrogen bond, saka silica gel haigone kushandiswa pakuomesa magasi aya. Kuumbwa kwesilica gel ndeyeSiO2 ·nH2 O, nzvimbo yakakura yesilica gel uye boka rakapfuma rehydroxyl riri pamusoro rinogadzira silica gel inogona kushandiswa seine-non-chepfu dryer nekushanda kwakanaka, uye inoshandiswa zvakanyanya mukugadzira uye hupenyu. . Mupepa iri, inosimbiswa kubva kune maviri maficha ekuyedza uye theoretical calculation kuti silica gel inogona adsorb NH3, HCl, SO2, CO2 nemamwe magasi kuburikidza neintermolecular hydrogen bond, saka silica gel haigone kushandiswa pakuomesa magasi aya.
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FIG. 6 Kudyidzana modhi pakati pemamorekuru akasiyana uye silica gel nzvimbo yakaverengerwa neDFT nzira
Nguva yekutumira: Nov-14-2023
