39.Yini i-acidity yamanzi kanye ne-alkalinity?
I-acidity yamanzi ibhekisela enanini lezinto eziqukethwe emanzini ezinganciphisa izisekelo eziqinile. Kunezinhlobo ezintathu zezinto ezakha i-asidi: ama-asidi aqinile angahlukanisa ngokuphelele i-H+ (njenge-HCl, i-H2SO4), ama-asidi abuthakathaka ahlukanisa kancane i-H+ (H2CO3, ama-organic acid), nosawoti ohlanganiswe ama-asidi aqinile nezisekelo ezibuthakathaka (njenge NH4Cl, FeSO4). I-Acidity ilinganiswa nge-titration ngesisombululo esiyisisekelo esiqinile. I-acidity elinganiswa nge-methyl orange njengenkomba ngesikhathi sokwenziwa kwe-titration ibizwa ngokuthi i-methyl orange acidity, kuhlanganise ne-asidi eyakhiwe uhlobo lokuqala lwe-asidi eqinile kanye nohlobo lwesithathu lukasawoti oqinile we-asidi; i-acidity elinganiswa nge-phenolphthalein njengoba inkomba ibizwa ngokuthi i-phenolphthalein acidity, Yisamba sezinhlobo ezintathu ezingenhla ze-acidity, ngakho-ke ibizwa nangokuthi i-acidity isiyonke. Amanzi emvelo ngokuvamile awanayo i-asidi eqinile, kodwa aqukethe ama-carbonates nama-bicarbonates enza amanzi abe alkaline. Uma kune-acidity emanzini, ngokuvamile kusho ukuthi amanzi angcoliswe i-asidi.
Ngokuphambene ne-acidity, i-alkalinity yamanzi ibhekisela enanini lezinto emanzini ezinganciphisa ama-asidi aqinile. Izinto ezakha i-alkalinity zihlanganisa izisekelo eziqinile (ezifana ne-NaOH, KOH) ezingahlukanisa ngokuphelele i-OH-, izisekelo ezibuthakathaka ezihlukanisa kancane i-OH- (njenge-NH3, C6H5NH2), nosawoti owenziwe ngezisekelo eziqinile nama-asidi abuthakathaka (njenge-Na2CO3, K3PO4, Na2S) nezinye izigaba ezintathu. I-alkalinity ikalwa nge-titration ngesisombululo se-asidi esiqinile. I-alkalinity elinganiswa kusetshenziswa i-methyl orange njengenkomba ngesikhathi sokushintsha i-titration iyisamba sezinhlobo ezintathu ezingenhla ze-alkalinity, ebizwa ngokuthi i-alkalinity ephelele noma i-methyl orange alkalinity; i-alkalinity ikalwa kusetshenziswa i-phenolphthalein njengoba inkomba ibizwa ngesisekelo se-phenolphthalein. I-Degree, okuhlanganisa i-alkalinity eyakhiwe uhlobo lokuqala lwesisekelo esiqinile kanye nengxenye ye-alkalinity eyakhiwe uhlobo lwesithathu lukasawoti oqinile we-alkali.
Izindlela zokulinganisa ze-acidity ne-alkalinity zifaka i-acid-base indicator titration kanye ne-potentiometric titration, ngokuvamile eguqulelwa ku-CaCO3 futhi ikalwa ngo-mg/L.
40.Ingakanani i-pH yamanzi?
Inani le-pH liyilogarithm enegethivu yomsebenzi we-hydrogen ion kusixazululo samanzi esilinganisiwe, okungukuthi, i-pH=-lgαH+. Ingenye yezinkomba ezisetshenziswa kakhulu ohlelweni lokuhlanza indle. Ngaphansi kwezimo ezingu-25oC, lapho inani le-pH lingu-7, imisebenzi yama-ion e-hydrogen nama-ion e-hydroxide emanzini ayalingana, futhi ukugxila okuhambisanayo ngu-10-7mol/L. Ngalesi sikhathi, amanzi awathathi hlangothi, futhi inani le-pH> 7 lisho ukuthi amanzi ane-alkaline. , kanye nenani le-pH<7 means the water is acidic.
Inani le-pH libonisa ubumuncu kanye ne-alkalinity yamanzi, kodwa alikwazi ukukhomba ngokuqondile ubumuncu kanye ne-alkalinity yamanzi. Isibonelo, i-acidity ye-0.1mol/L yesisombululo se-hydrochloric acid kanye nesisombululo se-acetic acid esingu-0.1mol/L nayo ingu-100mmol/L, kodwa amanani ayo e-pH ahluke kakhulu. Inani le-pH lesisombululo esingu-0.1mol/L se-hydrochloric acid ngu-1, kuyilapho Inani le-pH lika-0.1 mol/L isixazululo se-acetic acid lingu-2.9.
41. Yiziphi izindlela ezivame ukusetshenziswa zokulinganisa inani le-pH?
Emkhiqizweni wangempela, ukuze ubambe ngokushesha futhi kalula izinguquko enanini le-pH lamanzi angcolile angena endaweni yokuhlanza amanzi angcolile, indlela elula iwukukala cishe ngephepha lokuhlola i-pH. Kumanzi angcolile angenambala ngaphandle kokungcola okumisiwe, izindlela ze-colorimetric nazo zingasetshenziswa. Njengamanje, indlela yezwe lami ejwayelekile yokukala inani le-pH lekhwalithi yamanzi indlela ye-potentiometric (indlela ye-electrode yengilazi ye-GB 6920–86). Ngokuvamile akuthintwa umbala, i-turbidity, izinto ze-colloidal, ama-oxidants, nama-ejenti anciphisayo. Ingakwazi futhi ukukala i-pH yamanzi ahlanzekile. Ingakwazi futhi ukukala inani le-pH lamanzi angcolile embonini angcoliswe amadigri ahlukene. Lena futhi indlela esetshenziswa kabanzi yokukala inani le-pH ezindaweni eziningi zokuhlanza amanzi angcolile.
Umgomo wesilinganiso se-potentiometric yenani le-pH ukuthola amandla e-electrode ekhombisayo, okungukuthi, inani le-pH, ngokulinganisa umehluko ongaba khona phakathi kwe-electrode yengilazi kanye ne-electrode eyireferensi enamandla aziwayo. I-electrode eyireferensi ngokuvamile isebenzisa i-calomel electrode noma i-electrode ye-Ag-AgCl, kanti i-calomel electrode iyona esetshenziswa kakhulu. Umnyombo we-pH potentiometer iyi-amplifier ye-DC, ekhulisa amandla akhiqizwa i-electrode futhi ilibonise ekhanda lemitha ngendlela yezinombolo noma izikhombisi. Ama-potentiometer ngokuvamile afakwe idivayisi yesinxephezelo sezinga lokushisa ukuze alungise umphumela wokushisa kuma-electrode.
Umgomo wokusebenza wemitha ye-pH eku-inthanethi esetshenziswa ezitshalweni zokuhlanza amanzi angcolile yindlela ye-potentiometric, futhi izinyathelo zokuphepha zokusetshenziswa ziyafana nalezo zamamitha we-pH elabhorethri. Kodwa-ke, ngenxa yokuthi ama-electrode asetshenziswayo acwiliswa ngokuqhubekayo emanzini angcolile noma amathangi aeration nakwezinye izindawo eziqukethe inani elikhulu lamafutha noma ama-microorganisms isikhathi eside, ngaphezu kokudinga imitha ye-pH ukuthi ifakwe idivayisi yokuhlanza ezenzakalelayo yama-electrode, manual. ukuhlanza kuyadingeka futhi ngokusekelwe ezimeni zekhwalithi yamanzi kanye nolwazi lokusebenza. Ngokuvamile, imitha ye-pH esetshenziswa emanzini angenisayo noma ithangi lokungenisa umoya ihlanzwa mathupha kanye ngesonto, kanti imitha ye-pH esetshenziswa emanzini angcolile ingahlanzwa ngesandla kanye ngenyanga. Kumamitha e-pH angakala ngasikhathi sinye izinga lokushisa kanye ne-ORP nezinye izinto, kufanele agcinwe futhi anakekelwe ngokuya ngezinyathelo zokuphepha zokusetshenziswa ezidingekayo emsebenzini wokulinganisa.
42. Yiziphi izinyathelo zokuphepha zokukala inani le-pH?
⑴I-potentiometer kufanele igcinwe yomile futhi ingangeni uthuli, inikwe amandla njalo ukuze ilungiswe, futhi ingxenye yokuxhuma okuholayo okokufaka kwe-electrode kufanele igcinwe ihlanzekile ukuze kuvinjelwe amaconsi amanzi, uthuli, uwoyela, njll. ukuthi kungangeni. Qinisekisa ukubeka phansi okuhle uma usebenzisa amandla e-AC. Ama-potentiometer aphathekayo asebenzisa amabhethri omile kufanele amiselele amabhethri njalo. Ngesikhathi esifanayo, i-potentiometer kufanele ilinganiswe njalo futhi ifakwe ku-zero ukuze ikwazi ukulinganisa nokugcinwa. Uma isilungisiwe kahle, iphoyinti elinguziro le-potentiometer kanye nezilawuli zokulinganiswa nezokuma azikwazi ukuzungeziswa ngokuthanda kwakhe ngesikhathi sokuhlolwa.
⑵Amanzi asetshenziselwa ukulungisa isisombululo sebhafa esijwayelekile nokugeza i-electrode akumele aqukathe i-CO2, abe nevelu ye-pH ephakathi kuka-6.7 no-7.3, kanye ne-conductivity engaphansi kuka-2 μs/cm. Amanzi aphathwe nge-anion kanye ne-cation exchange resin angahlangabezana nale mfuneko ngemva kokubilisa nokuwayeka aphole. Isixazululo se-buffer esijwayelekile esilungisiwe kufanele sivalwe futhi sigcinwe ebhodleleni lengilazi eliqinile noma ibhodlela le-polyethylene, bese ligcinwa esiqandisini ngo-4oC ukuze kunwetshwe impilo yesevisi. Uma igcinwe endaweni evulekile noma ezingeni lokushisa legumbi, impilo yesevisi ngokuvamile ayikwazi ukudlula Izinyanga ezi-1, isilondolozi esisetshenzisiwe asikwazi ukubuyiselwa ebhodleleni lokugcina ukuze siphinde sisetshenziswe.
⑶ Ngaphambi kokulinganisa okusemthethweni, qala uhlole ukuthi ithuluzi, i-electrode, nebhafa evamile kujwayelekile yini. Futhi imitha ye-pH kufanele ilinganiswe njalo. Ngokuvamile umjikelezo wokulinganisa uyikota eyodwa noma uhhafu wonyaka, futhi indlela yokulinganisa amaphuzu amabili isetshenziselwa ukulinganisa. Okungukuthi, ngokuya ngebanga le-pH yenani lesampula elizohlolwa, izixazululo ezimbili ezijwayelekile zebhafa eziseduze nayo ziyakhethwa. Ngokuvamile, umehluko wenani le-pH phakathi kwezixazululo ezimbili zebhafa kufanele okungenani ube mkhulu kuno-2. Ngemva kokubeka isixazululo sokuqala, hlola isixazululo sesibili futhi. Umehluko phakathi komphumela wokuboniswa we-potentiometer kanye nenani le-pH elijwayelekile lesixazululo sebhafa sesibili esijwayelekile akufanele libe mkhulu kuneyunithi engu-0.1 pH. Uma iphutha likhulu kuneyunithi ye-pH engu-0.1, isisombululo sesithathu sebhafa esijwayelekile kufanele sisetshenziselwe ukuhlolwa. Uma iphutha lingaphansi kwamayunithi angu-0.1 pH ngalesi sikhathi, cishe kunenkinga ngesixazululo sebhafa sesibili. Uma iphutha liselikhulu kuneyunithi ye-pH engu-0.1, kukhona okungalungile nge-electrode futhi i-electrode idinga ukucutshungulwa noma kufakwe entsha.
⑷Lapho ufaka esikhundleni se-buffer ejwayelekile noma isampula, i-electrode kufanele igezwe ngokugcwele ngamanzi acwecwe, futhi amanzi axhunywe ku-electrode kufanele amuncwe ngephepha lokuhlunga, bese ehlanjululwa ngesixazululo esizolinganiswa ukuze kuqedwe ukuthonyana. Lokhu kubalulekile ekusetshenzisweni kwamabhafa abuthakathaka. Lokhu kubaluleke kakhulu uma usebenzisa izixazululo. Lapho ukala inani le-pH, isixazululo esinamanzi kufanele sinyakaziswe ngendlela efanele ukwenza isisombululo sifane futhi sifinyelele ukulingana kwe-electrochemical. Lapho kufundwa, ukunyakazisa kufanele kumiswe futhi kuvunyelwe kume isikhashana ukuvumela ukufundwa kuzinze.
⑸ Lapho ukala, qala ugeze ama-electrode amabili ngokucophelela ngamanzi, bese uhlanza ngesampula yamanzi, bese ucwilisa ama-electrode kubhekha oluncane oluqukethe isampula yamanzi, unyakazisa ibhekha ngokucophelela ngezandla zakho ukuze wenze iyunifomu yesampula yamanzi, bese urekhoda Inani le-pH ngemva kokufundwa lizinzile.
Isikhathi sokuthumela: Oct-26-2023
