39. Chii chinonzi acidity yemvura uye alkalinity?
Asidhi yemvura inoreva huwandu hwezvinhu zviri mumvura zvinokwanisa kudzikamisa mabhesi akasimba. Kune mhando nhatu dzezvinhu zvinoumba acidity: maasidhi akasimba anogona kusiyanisa zvachose H+ (yakadai seHCl, H2SO4), maasidhi asina simba anopatsanura zvishoma H+ (H2CO3, organic acids), uye munyu unoumbwa nemaasidhi akasimba uye mabhesi asina kusimba (senge NH4Cl, FeSO4). Acidity inoyerwa netitration ine yakasimba base solution. Iyo acidity yakayerwa nemethyl orange sechiratidzo panguva yetitration inonzi methyl orange acidity, kusanganisira iyo acidity inoumbwa nemhando yekutanga yeasidhi yakasimba uye yechitatu mhando yeasidhi yakasimba munyu; acidity yakayerwa nephenolphthalein sechiratidzo ichinzi phenolphthalein acidity, Ndiyo uwandu hwemhando nhatu dziri pamusoro dzeacidity, saka inodaidzwa zvakare kuti acidity yakazara. Mvura yechisikigo kazhinji haina asidhi yakasimba, asi ine carbonates nemabicarbonates anoita kuti mvura ive alkaline. Kana paine acidity mumvura, zvinowanzoreva kuti mvura yakasvibiswa neasidhi.
Kusiyana neacidity, alkalinity yemvura inoreva huwandu hwezvinhu zviri mumvura zvinogona kumisa maasidhi akasimba. Zvinhu zvinoumba alkalinity zvinosanganisira mabhesi akasimba (akadai seNaOH, KOH) anogona kuparadzanisa zvachose OH-, mabhesi asina simba anoparadzanisa OH- (senge NH3, C6H5NH2), uye munyu unoumbwa nemabhesi akasimba uye asina simba acids (seNa2CO3, K3PO4, Na2S) nemamwe mapoka matatu. Alkalinity inoyerwa netitration ine yakasimba acid solution. Iyo alkalinity yakayerwa uchishandisa methyl orange sechiratidzo panguva yetitration ndiyo huwandu hwemhando nhatu dziri pamusoro dzealkalinity, iyo inonzi yakazara alkalinity kana methyl orange alkalinity; iyo alkalinity yakayerwa uchishandisa phenolphthalein sechiratidzo chinonzi phenolphthalein base. Dhigirii, kusanganisira alkalinity yakaumbwa nemhando yekutanga yehwaro hwakasimba uye chikamu chealkalinity chakaumbwa nemhando yechitatu yealkali munyu wakasimba.
Nzira dzekuyera dze acidity uye alkalinity dzinosanganisira acid-base index titration uye potentiometric titration, iyo inowanzoshandurwa kuita CaCO3 uye kuyerwa mumg/L.
40.Chii chinonzi pH kukosha kwemvura?
Ukoshi hwepH ndiyo negative logarithm yehydrogen ion chiitiko mune yakayerwa aqueous solution, kureva, pH=-lgαH+. Icho chimwe chezvinonyanya kushandiswa zviratidzo mumutambo wekuchenesa tsvina. Pasi pe25oC mamiriro, kana pH kukosha iri 7, mabasa ehydrogen ions uye hydroxide ions mumvura akaenzana, uye chiyero chinoenderana 10-7mol / L. Panguva ino, mvura haina kwayakarerekera, uye pH kukosha> 7 zvinoreva kuti mvura ine alkaline. , uye pH kukosha<7 means the water is acidic.
Iyo pH kukosha inoratidza acidity uye alkalinity yemvura, asi haigone kuratidza zvakananga acidity uye alkalinity yemvura. Semuenzaniso, acidity ye0.1mol/L hydrochloric acid solution uye 0.1mol/L acetic acid solution zvakare 100mmol/L, asi pH yavo yakatosiyana. Iyo pH kukosha kwe0.1mol/L hydrochloric acid mhinduro ndeye 1, nepo Iyo pH kukosha kwe0.1 mol/L acetic acid mhinduro ndeye 2.9.
41. Ndedzipi nzira dzinowanzoshandiswa dzekuyera pH kukosha?
Mukugadzirwa chaiko, kuitira kukurumidza uye nyore kubata shanduko yepH kukosha kwemvura yetsvina ichipinda munzvimbo yekuchenesa mvura yetsvina, nzira iri nyore ndeyekuiyera nepH bvunzo bepa. Kune mvura isina ruvara isina tsvina isina kusvibiswa yakamiswa, nzira dze colorimetric dzinogona kushandiswa zvakare. Parizvino, nzira yenyika yangu yekuyera iyo pH kukosha kwemhando yemvura ndiyo potentiometric nzira (GB 6920-86 girazi electrode nzira). Iyo kazhinji haina kukanganiswa nemuvara, turbidity, colloidal zvinhu, oxidants, uye zvinoderedza vamiririri. Inogonawo kuyera pH yemvura yakachena. Inogona zvakare kuyera iyo pH kukosha kwemvura yetsvina yemaindasitiri yakasvibiswa kune madhigirii akasiyana. Iyi zvakare inzira inoshandiswa zvakanyanya yekuyera pH kukosha mune yakawanda tsvina yekuchenesa zvidyarwa.
Nheyo ye potentiometric kuyerwa kwepH kukosha ndeyekuwana mukana weiyo inoratidzira electrode, kureva, iyo pH kukosha, nekuyera mutsauko unokwanisa pakati pegirazi electrode uye referenzi electrode ine inozivikanwa inogoneka. Iyo referensi electrode inowanzo shandisa calomel electrode kana Ag-AgCl electrode, ine calomel electrode iri iyo inonyanya kushandiswa. Nheyo yepH potentiometer ndeye DC amplifier, iyo inokwidziridza iyo inogona kugadzirwa neelectrode uye inoiratidza pamusoro wemamita muchimiro chenhamba kana anonongedzera. Potentiometers anowanzo kuve akashongedzerwa nemudziyo wekuripira tembiricha kugadzirisa mabatiro etembiricha pama electrode.
Musimboti wekushanda wepamhepo pH mita inoshandiswa mumarabhoritari ekuchenesa mvura inzira ye potentiometric, uye matanho ekushandisa akanyanya kufanana neaya erabhoritari pH metres. Nekudaro, nekuti maelectrodes anoshandiswa anogara akanyudzwa mumvura yetsvina kana aeration matangi uye dzimwe nzvimbo dzine huwandu hwakakura hwemafuta kana tupukanana kwenguva yakareba, mukuwedzera pakuda kuti pH mita ive ine otomatiki yekuchenesa mudziyo wemagetsi, bhuku rekushandisa. kuchenesa kunodiwawo zvichienderana nemamiriro ehutano hwemvura uye ruzivo rwekushanda. Kazhinji, iyo pH mita inoshandiswa mumvura inopinza kana aeration tank inocheneswa nemaoko kamwechete pasvondo, nepo pH mita inoshandiswa mumvura ine tsvina inogona kucheneswa nemaoko kamwe chete pamwedzi. Kune pH metres inogona panguva imwe chete kuyera tembiricha uye ORP nezvimwe zvinhu, zvinofanirwa kuchengetedzwa uye kuchengetedzwa zvinoenderana nechenjedzo rekushandisa rinodiwa pakuyera basa.
42.Ndeipi matanho ekuyera kuyera pH kukosha?
⑴Iyo potentiometer inofanirwa kuchengetwa yakaoma uye isina guruva, inobatidzwa nguva nenguva kuitira kugadzirisa, uye chikamu chekubatanidza chinotungamira chikamu che electrode chinofanira kuchengetedzwa chakachena kudzivirira madonhwe emvura, guruva, mafuta, nezvimwe. Iva nechokwadi chekudzika kwakanaka kana uchishandisa AC simba. Portable potentiometers anoshandisa mabhatiri akaoma anofanira kutsiva mabhatiri nguva dzose. Panguva imwecheteyo, iyo potentiometer inofanirwa kugara yakagadziriswa uye zeroed yekuenzanisa uye kugadzirisa. Kana yangogadziriswa nemazvo, zero point ye potentiometer uye calibration uye zvigadziriso zvekumira hazvigone kutenderedzwa pakuda panguva yekuyedzwa.
⑵Mvura inoshandiswa kugadzira yakajairwa buffer solution nekugezesa electrode haifanire kunge iine CO2, ine pH value iri pakati pe6.7 ne7.3, uye conductivity isingasviki 2 μs/cm. Mvura yakabikwa neanion uye cation exchange resin inogona kusangana nezvinodiwa izvi mushure mekuvira nekuirega ichitonhorera. Iyo yakagadzirwa yakajairwa buffer mhinduro inofanirwa kuvharwa uye kuchengetwa mubhodhoro regirazi rakaomarara kana polyethylene bhodhoro, uye yozochengetwa mufiriji pa4oC kuwedzera hupenyu hwebasa. Kana yakachengetwa pamhepo kana pamhepo tembiricha, hupenyu hwesevhisi kazhinji haugone kudarika Mwedzi 1, buffer yakashandiswa haigone kudzoserwa mubhodhoro rekuchengetedza kuti ishandiswezve.
⑶ Usati wayera kuyera, tanga watarisa kana chiridzwa, electrode, uye standard buffer zvakajairika. Uye iyo pH mita inofanirwa kuverengerwa nguva nenguva. Kazhinji iyo calibration kutenderera ikota kana hafu yegore, uye maviri-poinzi calibration nzira inoshandiswa pakugadzirisa. Kureva kuti, zvinoenderana neiyo pH kukosha kweiyo sampuli kuti iongororwe, maviri akajairwa buffer mhinduro ari padyo nayo anosarudzwa. Kazhinji, musiyano wekukosha kwepH pakati pezvigadziriso zviviri zvebhafa zvinofanira kunge zvakakura kudarika 2. Mushure mekuisa nemhinduro yekutanga, edzai mhinduro yechipiri zvakare. Musiyano uripo pakati pechiratidziro mhedzisiro ye potentiometer uye yakajairwa pH kukosha kwechipiri yakajairwa buffer mhinduro haifanire kunge yakakura kupfuura 0.1 pH unit. Kana kukanganisa kwakakura kupfuura 0.1 pH unit, yechitatu yakajairwa buffer mhinduro inofanirwa kushandiswa kuyedza. Kana kukanganisa kuri kushoma pane 0.1 pH mayunitsi panguva ino, panogona kunge paine dambudziko nemhinduro yechipiri buffer. Kana kukanganisa kuchiri kwakakura kudarika 0.1 pH unit, pane chimwe chinhu chisina kunaka ne electrode uye electrode inoda kugadziriswa kana kutsiviwa neimwe itsva.
⑷Paunenge uchitsiva iyo yakajairwa buffer kana sampuli, iyo electrode inofanira kugezwa zvizere nemvura yakanyungudutswa, uye mvura yakanamirwa paelectrode inofanira kutorwa nesefa bepa, yozosukurudzwa nemushonga wekuyerwa kuti ubvise kufurirana. Izvi zvakakosha pakushandisa zvisina simba buffers. Izvi zvinonyanya kukosha kana uchishandisa mhinduro. Pakuyera kukosha kwepH, mhinduro ine aqueous inofanira kumutswa zvakakodzera kuita kuti mhinduro ifanane uye iwane electrochemical equilibrium. Pakurava, kunyandura kunofanira kumiswa ndokubvumirwa kumira kwechinguvana kuti kurava kuve kwakatsiga.
⑸ Pakuyera, tanga wageza maelectrode maviri zvakanaka nemvura, wozogeza nesample yemvura, wonyudza maelectrode mubeaker diki rine sampu yemvura, zunza beaker nemawoko ako kugadzira yunifomu yemvura, uye rekodha pH kukosha mushure mekuverenga kwakagadzikana.
Nguva yekutumira: Oct-26-2023
