Hauv kev lag luam dej thiab kev kho dej khib nyiab, ion pauv softening yog ib qho ntawm cov classic thiab dav siv dej zoo tswj technologies. Txawm hais tias "resin exchange" yog ib lo lus paub rau engineers, lub hauv paus ion equilibrium thiab reversible reversible mechanisms ncaj qha txiav txim siab softening nyhuv, resin lifespan, thiab regeneration economics. Nrog rau qhov tshwm sim ntawm cov txheej txheem tshiab xws li siab- dej qab ntsev thiab xoom- cov kab hluav taws xob tawm, cov qauv kev sib pauv ion tsoos tau ntsib cov teeb meem tshiab- yog vim li cas softening efficiency txo qis hauv siab - dej qab ntsev? Vim li cas thiaj yuav tsum tau ua kom rov tsim dua brine concentration ntawm 6% -10%? Kab lus no yuav pib nrog cov tshuaj sib npaug ntawm kev sib pauv ion, sib sib zog nqus cov cai tseem ceeb ntawm cov tshuaj tiv thaiv ntawm cation txauv resins thaum lub sij hawm hloov, softening, thiab rov tsim dua tshiab, muab theoretical hauv paus thiab cov tswv yim qhia rau engineers optimize system operating tsis.
I. Cov Ntsiab Cai Tseem Ceeb ntawm Ion Txauv thiab Kev Txhim Kho
Kev hloov pauv, softening, thiab rov tsim cov txheej txheem ntawm cation txauv resins yog qhov tseem ceeb ntawm cov txheej txheem ion pauv, zoo ib yam li cov tshuaj tiv thaiv hauv kev daws, tshwj tsis yog tias lawv tshwm sim hauv cov khoom sib txawv (khoom thiab kua). Ua ntej thiab tom qab cov tshuaj tiv thaiv, cov qauv resin nws tus kheej tsis hloov. Qhov no "leej twg pauv leej twg" teeb meem yog qhov tseem ceeb ntawm cov txheej txheem rov qab los. Rau kev sib pauv ion kom ua tau zoo, cov tshuaj sib npaug yuav tsum raug cuam tshuam, thawb cov tshuaj tiv thaiv mus rau sab xis thiab tshem tawm ntau npaum li cov khoom tsim tshiab li sai tau los ntawm kev daws. Kev sib pauv ntawm RNa- hom resin thiab CaCl2 ua piv txwv, raws li qhia hauv kab zauv hauv qab no:
Raws li cov tshuaj sib npaug, cov tshuaj tiv thaiv zoo li qub hauv qhov sib npaug saum toj no nce mus txog lub xeev sib npaug tom qab qee qhov taw tes, txhais tau tias tsis yog tag nrho Na + ntawm RNa resin tau pauv. Txhawm rau ua kom cov dej softening thiab thawb cov tshuaj tiv thaiv mus rau sab xis, NaCl generated yuav tsum raug tshem tawm tam sim ntawd.
Raws li txoj cai no, hauv kev xyaum ua ntau lawm, RNa- hom resin yog muab tso rau hauv ib qho kev sib hloov ion, tso cai rau cov dej uas muaj CaCl2 ntws mus tas li, yog li tsis tu ncua tshem tawm cov NaCl generated. Ua li no, Na + ions ntawm cov resin tuaj yeem hloov pauv txuas ntxiv nrog Ca2+ ions hauv dej kom txog thaum yuav luag tag nrho Na + ions ntawm cov resin pauv. Qhov no yog lub hauv paus ntsiab lus ntawm ion pauv. Cov txheej txheem rov tsim dua tshiab yog qhov txawv: Na+ ions pauv nrog Ca2+ ions ntawm R2Ca- hom resin, thiab cov khoom tsim tawm CaCl2 raug tshem tawm sai, uas muaj txiaj ntsig zoo rau kev rov tsim dua tshiab.
II. Equilibrium thiab cuam tshuam ntawm Ion Exchange
Cov tshuaj tiv thaiv rov qab los ntawm kev sib pauv ion ua raws li "txoj cai ntawm kev ua haujlwm loj," thiab qhov sib npaug ntawm K ntawm ion pauv cov tshuaj tiv thaiv tuaj yeem qhia tau los ntawm cov qauv hauv qab no:
Qhov twg: [Ca2+]e yog qhov concentration ntawm Ca2+ ntawm cov resin ntawm cov tshuaj tiv thaiv equilibrium; [Na +] e yog qhov concentration ntawm Na + ntawm cov resin ntawm cov tshuaj tiv thaiv equilibrium; [Ca2+] yog qhov concentration ntawm Ca2+ nyob rau hauv cov dej ntawm cov tshuaj tiv thaiv equilibrium; [Na +]e yog qhov concentration ntawm Na + hauv dej ntawm cov tshuaj tiv thaiv sib npaug.
Sab laug ntawm cov mis saum toj no sawv cev rau qhov piv ntawm Ca2+ concentration rau Na + concentration hauv cov resin. Yog tias tus nqi no loj, nws qhia tau tias Ca2+ concentration ntau dua li Na + concentration, thiab cov resin tseem ceeb ntawm hom R2Ca; yog tias tus nqi no me me, cov resin yog qhov tseem ceeb ntawm RNa hom. Lub qub yog qhov yuav tsum tau rau softening nyhuv, thiab tom kawg yog qhov yuav tsum tau rau cov nyhuv regeneration.
Raws li pom tau los ntawm cov qauv, qhov loj ntawm [Ca2+]e/[Na+]e² nyob ntawm qhov sib npaug ntawm qhov K thiab qhov loj ntawm [Ca2+]/[Na+]² hauv dej. Kev txheeb xyuas ntawm ob yam no yog raws li hauv qab no:
(1) Tus nqi K yog qhov tsis tu ncua ntau dua 1, yog li cuam tshuam qhov kev xav ntawm lub hauv paus rau Ca2+ los hloov Na + ntawm ob ions. Qhov kev xav no yog txiav txim siab los ntawm kev sib pauv peev xwm ntawm ob ions thiab cov resin nws tus kheej, xav txog qhov tseem ceeb ntawm "leej twg pauv leej twg."
(2) [Ca2+]/[Na+]2 yam qhia txog qhov txheeb ze ntawm Ca2+ thiab Na+ hauv dej. Qhov kev sib raug zoo no hloov pauv nrog cov dej zoo thiab tuaj yeem cuam tshuam kev dag ntxias.
Thaum siv cov ion txauv los ua kom cov dej tsis qab ntsev, ob qho tib si Ca2+ thiab Na + concentrations tsawg, tab sis Ca2+ concentration yog ntau dua li Na + concentration. Qhov no ua rau muaj qhov loj [Ca2+]/[Na+]2 tus nqi. Txij li thaum tus nqi K tseem ntau dua 1, cov khoom ntawm ob qhov tseem loj dua, ua rau muaj tus nqi loj [Ca2+]e/[Na+]e2 tus nqi. Qhov no qhia tau hais tias tom qab ion pauv, cov resin yog qhov tseem ceeb ntawm R2Ca hom. Thaum siv cov ion txauv los ua kom cov dej qab ntsev ntau dua, qhov ntau ntawm Ca²⁺ thiab Na⁺ hauv dej yog siab heev, thaum lub concentration ntawm Ca²⁺ qis dua Na⁺. Qhov no ua rau tus nqi me me [Ca²⁺]/[Na⁺]² tus nqi, uas, thaum muab tus nqi K, kuj tsawg heev. Yog li ntawd, nws yog qhov nyuaj kom tau txais qhov loj [Ca²⁺]e / [Na⁺]e² tus nqi, txhais tau hais tias cov resin nyuaj rau hloov mus rau R₂Ca daim ntawv thaum sib pauv ion. Qhov no qhia txog qhov nyuaj ntawm kev siv ion txauv los ua kom cov dej qab ntsev ntau dua -.
Thaum lub sij hawm rov tsim dua tshiab, peb xav kom cov resin hloov dua siab tshiab rau hauv daim ntawv RNa. Txhawm rau ua kom [Ca²⁺]e/[Na⁺]e² tus nqi me me, tib txoj hauv kev ua tau yog kom nce Na⁺ concentration hauv dej. Qhov no yog vim li cas ntsev concentration thaum lub sij hawm rov tsim dua yuav tsum ncav cuag 6% ~ 10%.
Rau kev rov tsim dua tshiab ntawm RH- hom resin, yog HCl raug siv los ua cov regenerant, CaCl₂ thiab MgCl₂ raug tsim. Ob leeg ntawm cov tshuaj no muaj cov solubility siab hauv dej, yog li tsis muaj teeb meem nag lossis daus. Yog li ntawd, tsis muaj kev txwv tshwj xeeb ntawm qhov concentration ntawm HCl tov. Txawm li cas los xij, thaum siv H2SO4 ua lub tshuab hluav taws xob, qhov solubility ntawm qhov tshwm sim CaSO4 (gypsum) tsawg heev. Yog li, nws yog ib qho tseem ceeb los tiv thaiv CaSO4 nag lossis daus. Cov dej nag tuaj yeem thaiv cov resin tus ntoo khaub lig-txuas network pores, ua rau cov resin poob qee qhov kev sib pauv. Yog li, thaum siv H2SO4 ua ib qho kev tsim dua tshiab, cov concentration yuav tsum raug txwv rau 1% -2%, thiab tus nqi rov tsim dua yuav tsum tsis txhob qis dhau.
Hauv cov ntsiab lus, kev sib pauv ion tsis yog tsuas yog lub cev adsorption xwb, tab sis kev hloov pauv hloov pauv tau tswj hwm los ntawm cov tshuaj sib npaug. Kev nkag siab txog nws cov ntsiab lus tseem ceeb yog qhov tseem ceeb rau kev siv tswv yim engineering. Rau cov tshuab softening, mastering kev sib raug zoo ntawm cov tshuaj tiv thaiv equilibrium tas li thiab cov ion concentration nyob rau hauv cov dej yog qhov tseem ceeb rau kev ua tau zoo pauv thiab economic regeneration. Rau siab -kev kho dej qab ntsev, nws tseem ceeb dua kom kov yeej cov kev txwv sib npaug los ntawm kev kho cov kev ua haujlwm lossis siv cov txheej txheem sib xyaw. Txawm hais tias rau kev lag luam dej los yog cov dej khib nyiab rov siv dua, kev xaiv thiab kev tsim kho tshiab ntawm ion txauv resins yog qhov tseem ceeb rau kev ua haujlwm ruaj khov thiab kev txuag hluav taws xob. Tsuas yog los ntawm kev sib txuas txoj kev xav nrog cov kev paub dhau los tuaj yeem ua tus nqi tseem ceeb ntawm kev sib pauv ion tshuab hauv kev kho dej niaj hnub no tiag tiag.