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Iziphepho zothuli ziyingozi enkulu emazweni amaningi emhlabeni jikelele ngenxa yomthelela wazo owonakalisayo kwezolimo, empilweni yabantu, kumanethiwekhi ezokuthutha kanye nengqalasizinda. Ngenxa yalokho, ukuguguleka komoya kubhekwa njengenkinga yomhlaba wonke. Enye yezindlela ezinobungani nemvelo zokunqanda ukuguguleka komoya ukusetshenziswa kwe-microbial induced carbonate precipitation (MICP). Kodwa-ke, imikhiqizo engaphansi kwe-MICP esekelwe ekuwohlokeni kwe-urea, njenge-ammonia, ayifaneleki uma ikhiqizwa ngobuningi. Lolu cwaningo luveza amafomula amabili e-calcium formate bacteria ukuze kubhujiswe i-MICP ngaphandle kokukhiqiza i-urea futhi luqhathanisa ngokuphelele ukusebenza kwawo namafomula amabili e-non-ammonia-producing calcium acetate bacteria. Amagciwane acatshangwayo yi-Bacillus subtilis kanye ne-Bacillus amyloliquefaciens. Okokuqala, kwanqunywa amanani alungiselelwe ezici ezilawula ukwakheka kwe-CaCO3. Ukuhlolwa kwemigudu yomoya kwabe sekwenziwa kumasampula esihlabathi aphathwe ngamafomula alungiselelwe, futhi kwalinganiswa ukumelana nokuguguleka komoya, ijubane lokuvala umkhawulo, kanye nokumelana nokubhomba kwesihlabathi. Ama-allomorph e-Calcium carbonate (CaCO3) ahlolwe kusetshenziswa i-optical microscopy, i-scanning electron microscopy (SEM), kanye nokuhlaziywa kwe-X-ray diffraction. Ama-formulations asekelwe kwi-calcium formate enze kangcono kakhulu kune-acetate-based formulations ngokuya ngokwakhiwa kwe-calcium carbonate. Ngaphezu kwalokho, i-B. subtilis ikhiqize i-calcium carbonate eningi kune-B. amyloliquefaciens. Ama-micrograph e-SEM abonise ngokusobala ukubopha kanye nokunyatheliswa kwamagciwane asebenzayo nangasebenzi ku-calcium carbonate okubangelwa ukuchitheka. Wonke ama-formulations anciphise kakhulu ukuguguleka komoya.
Ukuguguleka komoya sekuyisikhathi eside kwaziwa njengenkinga enkulu ebhekene nezifunda ezomile nezingenawo umswakama njengaseningizimu-ntshonalanga ye-United States, entshonalanga yeShayina, eSaharan Africa, kanye nengxenye enkulu yeMpumalanga Ephakathi1. Imvula encane ezindaweni ezomile nezingenawo umswakama iguqule izingxenye ezinkulu zalezi zifunda zaba yizingwadule, izindunduma zesihlabathi, kanye nezindawo ezingalinywanga. Ukuguguleka komoya okuqhubekayo kubeka izinsongo zemvelo engqalasizinda efana namanethiwekhi ezokuthutha, umhlaba wezolimo, kanye nomhlaba wezimboni, okuholela ezimweni ezimbi zokuphila kanye nezindleko eziphezulu zentuthuko yasemadolobheni kulezi zifunda2,3,4. Okubalulekile, ukuguguleka komoya akuthinti nje kuphela indawo lapho kwenzeka khona, kodwa futhi kubangela izinkinga zempilo nezomnotho emiphakathini ekude njengoba kuthutha izinhlayiya ngomoya ziye ezindaweni ezikude nomthombo5,6.
Ukulawulwa kokuguguleka komoya kuseyinkinga yomhlaba wonke. Izindlela ezahlukene zokuzinzisa inhlabathi zisetshenziswa ukulawula ukuguguleka komoya. Lezi zindlela zifaka phakathi izinto ezifana nokusetshenziswa kwamanzi7, ama-mulch kawoyela8, ama-biopolymer5, i-microbial induced carbonate precipitation (MICP)9,10,11,12 kanye ne-enzyme induced carbonate precipitation (EICP)1. Ukumanzisa inhlabathi kuyindlela ejwayelekile yokucindezela uthuli ensimini. Kodwa-ke, ukuhwamuka kwayo okusheshayo kwenza le ndlela isebenze kahle ezindaweni ezomile nezingenawo umswakama1. Ukusetshenziswa kwamakhemikhali e-mulching kawoyela kwandisa ukuhlangana kwesihlabathi kanye nokungqubuzana phakathi kwezinhlayiya. Impahla yazo ehlangene ibopha izinhlamvu zesihlabathi ndawonye; noma kunjalo, ama-mulch kawoyela nawo adala ezinye izinkinga; umbala wawo omnyama wandisa ukumuncwa kokushisa futhi uholela ekufeni kwezitshalo nama-microorganism. Iphunga lawo kanye nentuthu kungabangela izinkinga zokuphefumula, futhi okubaluleke kakhulu, izindleko zawo eziphakeme kungenye isithiyo. Ama-biopolymer angenye yezindlela ezisanda kuphakanyiswa ezinobungani nemvelo zokunciphisa ukuguguleka komoya; akhishwa emithonjeni yemvelo njengezitshalo, izilwane kanye namagciwane. I-Xanthan gum, i-guar gum, i-chitosan kanye ne-gellan gum yi-biopolymers esetshenziswa kakhulu ekusetshenzisweni kobunjiniyela5. Kodwa-ke, ama-biopolymer ancibilikayo emanzini angalahlekelwa amandla futhi aphume enhlabathini uma evezwa emanzini13,14. I-EICP iboniswe iyindlela ephumelelayo yokucindezela uthuli lwezinhlelo zokusebenza ezahlukahlukene okuhlanganisa imigwaqo engagandayiwe, amachibi asemuva kanye nezindawo zokwakha. Nakuba imiphumela yayo iyakhuthaza, ezinye izinkinga ezingaba khona kumele zicatshangelwe, njengezindleko kanye nokuntuleka kwezindawo ze-nucleation (okusheshisa ukwakheka kanye nokuna kwe-CaCO3 crystals15,16).
I-MICP yaqala ukuchazwa ngasekupheleni kwekhulu le-19 nguMurray no-Irwin (1890) kanye noSteinmann (1901) ocwaningweni lwabo lokuwohloka kwe-urea yizinto ezincane zasolwandle17. I-MICP inqubo yemvelo eyenzeka ngokwemvelo ehilela imisebenzi eyahlukahlukene yamagciwane kanye nezinqubo zamakhemikhali lapho i-calcium carbonate ibangelwa khona ukusabela kwama-ion e-carbonate avela kuma-metabolites amancane anama-ion e-calcium endaweni ezungezile18,19. I-MICP ehilela umjikelezo we-nitrogen obola i-urea (i-MICP ebola i-urea) uhlobo oluvame kakhulu lokuhlanzeka kwe-carbonate okubangelwa yizinto ezincane, lapho i-urease ekhiqizwa amabhaktheriya ivuselela i-hydrolysis ye-urea20,21,22,23,24,25,26,27 kanje:
Ku-MICP ehilela umjikelezo wekhabhoni we-organic salt oxidation (i-MICP engenalo uhlobo lokuwohloka kwe-urea), amabhaktheriya e-heterotrophic asebenzisa usawoti we-organic njenge-acetate, i-lactate, i-citrate, i-succinate, i-oxalate, i-malate kanye ne-glyoxylate njengemithombo yamandla ukukhiqiza amaminerali e-carbonate28. Lapho kukhona i-calcium lactate njengomthombo wekhabhoni kanye nama-ion e-calcium, ukusabela kwamakhemikhali kokwakheka kwe-calcium carbonate kuboniswa ku-equation (5).
Enqubweni ye-MICP, amangqamuzana ebhaktheriya ahlinzeka ngezindawo ze-nucleation ezibaluleke kakhulu ekuthuthweni kwe-calcium carbonate; ubuso bamangqamuzana ebhaktheriya bushajwa kabi futhi bungasebenza njengesithasiselo se-divalent cations njenge-calcium ion. Ngokufaka ama-calcium ion kumaseli ebhaktheriya, lapho ukuhlushwa kwama-carbonate ion kwanele, ama-calcium cation nama-carbonate anion ayasabela bese i-calcium carbonate ingena ebusweni bamabhaktheriya29,30. Inqubo ingafingqwa kanje31,32:
Amakristalu e-calcium carbonate akhiqizwa yi-bioaverage angahlukaniswa ngezinhlobo ezintathu: i-calcite, i-vaterite, kanye ne-aragonite. Phakathi kwazo, i-calcite kanye ne-vaterite yiwona ama-allomorphs e-calcium carbonate abangelwa amagciwane avame kakhulu33,34. I-Calcite iyi-allomorphs ye-calcium carbonate ezinze kakhulu ku-thermodynamically. Nakuba i-vaterite ibikwe ukuthi iyakwazi ukuguquguquka, ekugcineni iguquka ibe yi-calcite36,37. I-Vaterite iyona eqine kakhulu kulawa makristalu. Iyikristalu enezinhlangothi eziyisithupha enekhono lokugcwalisa imbobo elingcono kunezinye amakristalu e-calcium carbonate ngenxa yobukhulu bayo obukhulu38. Kokubili i-MICP ewohlokile yi-urea kanye ne-urea-undegraded ingaholela ekuweni kwe-vaterite13,39,40,41.
Nakuba i-MICP ibonise amandla athembisayo ekuzinziseni inhlabathi enenkinga kanye nenhlabathi esengozini yokuguguleka komoya42,43,44,45,46,47,48, enye yemikhiqizo engaphansi kwe-urea hydrolysis yi-ammonia, engabangela izinkinga zempilo ezincane kuya kwezinzima kuye ngezinga lokuchayeka49. Lo mphumela ohlangothini wenza ukusetshenziswa kwalobu buchwepheshe kube yimpikiswano, ikakhulukazi lapho izindawo ezinkulu zidinga ukwelashwa, njengokunciphisa uthuli. Ngaphezu kwalokho, iphunga le-ammonia alibekezeleleki lapho inqubo yenziwa ngamanani aphezulu okusetshenziswa kanye nobuningi obukhulu, okungathinta ukusebenza kwayo okusebenzayo. Nakuba izifundo zakamuva zibonise ukuthi ama-ion e-ammonium angancishiswa ngokuwaguqula abe eminye imikhiqizo efana ne-struvite, lezi zindlela azisusi ngokuphelele ama-ion e-ammonium50. Ngakho-ke, kusenesidingo sokuhlola ezinye izixazululo ezingakhiqizi ama-ion e-ammonium. Ukusetshenziswa kwezindlela zokuwohloka kwe-non-urea ze-MICP kunganikeza ikhambi elingaba khona elingahlolwanga kahle kumongo wokunciphisa ukuguguleka komoya. UFattahi et al. baphenye ukuwohloka kwe-MICP okungena-urea besebenzisa i-calcium acetate kanye ne-Bacillus megaterium41, kuyilapho uMohebbi nabanye basebenzisa i-calcium acetate kanye ne-Bacillus amyloliquefaciens9. Kodwa-ke, ucwaningo lwabo aluzange luqhathaniswe neminye imithombo ye-calcium kanye namabhaktheriya e-heterotrophic angagcina ethuthukise ukumelana nokuguguleka komoya. Kukhona nokuntuleka kwezincwadi eziqhathanisa izindlela zokuguguleka okungena-urea nezindlela zokuguguleka komoya ekunciphiseni ukuguguleka komoya.
Ngaphezu kwalokho, ucwaningo oluningi lokuguguleka komoya kanye nokulawula uthuli luye lwenziwa kumasampula enhlabathi anezindawo ezisicaba.1,51,52,53 Kodwa-ke, izindawo ezisicaba azivamile kakhulu ngokwemvelo kunezintaba kanye nezigodi. Yingakho izindunduma zesihlabathi ziyisici sendawo esivame kakhulu ezindaweni eziwugwadule.
Ukuze kunqotshwe ukushiyeka okukhulunywe ngakho ngenhla, lolu cwaningo luhlose ukwethula isethi entsha yama-bacteria angewona akhiqiza i-ammonia. Ngale njongo, sicabangele izindlela ze-MICP ezingezona ezonakalisayo ze-urea. Kuhlolwe ukusebenza kahle kwemithombo emibili ye-calcium (i-calcium formate ne-calcium acetate). Ngokwazi kwababhali, ukuhlanzwa kwe-carbonate kusetshenziswa inhlanganisela emibili yemithombo ye-calcium kanye ne-bacteria (okungukuthi i-calcium formate-Bacillus subtilis kanye ne-calcium formate-Bacillus amyloliquefaciens) akukahlolwa ezifundweni zangaphambilini. Ukukhethwa kwala ma-bacteria kwakusekelwe kuma-enzyme awakhiqizayo avuselela ukushiswa kwe-calcium formate ne-calcium acetate ukuze kwakheke ukuhlanzwa kwe-microbial carbonate. Saklama ucwaningo olunzulu lokuhlola ukuthola izici ezifanele njenge-pH, izinhlobo zamabhaktheriya kanye nemithombo ye-calcium kanye nokuhlushwa kwawo, isilinganiso samabhaktheriya nesisombululo somthombo we-calcium kanye nesikhathi sokwelapha. Ekugcineni, ukusebenza kahle kwaleli qoqo lama-bacterial agents ekuvimbeleni ukuguguleka komoya ngokusebenzisa i-calcium carbonate precipitation kuhlolwe ngokwenza uchungechunge lwezivivinyo zomoya ezindundumeni zesihlabathi ukuze kutholakale ubukhulu bokuguguleka komoya, ijubane lokuqhekeka komkhawulo kanye nokumelana komoya we-bombardment yesihlabathi, kanye nokulinganiswa kwe-penetrometer kanye nezifundo ze-microstructural (isb. ukuhlaziywa kwe-X-ray diffraction (XRD) kanye ne-scanning electron microscopy (SEM)) nakho kwenziwa.
Ukukhiqizwa kwe-calcium carbonate kudinga ama-ion e-calcium nama-ion e-carbonate. Ama-ion e-calcium angatholakala emithonjeni ehlukahlukene ye-calcium njenge-calcium chloride, i-calcium hydroxide, kanye ne-skim milk powder54,55. Ama-ion e-carbonate angakhiqizwa ngezindlela ezahlukene ze-microbial njenge-urea hydrolysis kanye ne-aerobic noma i-anaerobic oxidation yezinto eziphilayo56. Kulolu cwaningo, ama-ion e-carbonate atholakala ekusabeleni kwe-oxidation kwe-formate ne-acetate. Ngaphezu kwalokho, sisebenzise usawoti we-calcium we-formate ne-acetate ukukhiqiza i-calcium carbonate emsulwa, ngakho-ke i-CO2 ne-H2O kuphela ezitholakale njengemikhiqizo elandelanayo. Kule nqubo, into eyodwa kuphela esebenza njengomthombo we-calcium kanye nomthombo we-carbonate, futhi akukho ammonia ekhiqizwayo. Lezi zici zenza indlela yokukhiqiza umthombo we-calcium kanye ne-carbonate esiyicabange ukuthi ithembisa kakhulu.
Ukusabela okuhambisanayo kwe-calcium formate kanye ne-calcium acetate ukwakha i-calcium carbonate kuboniswe kumafomula (7)-(14). Amafomula (7)-(11) abonisa ukuthi i-calcium formate iyancibilika emanzini ukuze yakhe i-formic acid noma i-formate. Ngakho-ke ikhambi liwumthombo wama-ion e-calcium ne-hydroxide amahhala (amafomula 8 no-9). Ngenxa yokushiswa kwe-formic acid, ama-athomu e-carbon ku-formic acid aguqulwa abe yi-carbon dioxide (ifomula 10). I-calcium carbonate ekugcineni iyakhiwa (amafomula 11 no-12).
Ngokufanayo, i-calcium carbonate yakhiwa nge-calcium acetate (izilinganiso 13–15), ngaphandle kokuthi i-acetic acid noma i-acetate yakhiwa esikhundleni se-formic acid.
Ngaphandle kokuba khona kwama-enzyme, i-acetate ne-formate azikwazi uku-oxidized ekamelweni lokushisa. I-FDH (formate dehydrogenase) kanye ne-CoA (coenzyme A) zivuselela uku-oxidation kwe-formate ne-acetate ukuze kwakhiwe i-carbon dioxide, ngokulandelana (Eqs. 16, 17) 57, 58, 59. Amabhaktheriya ahlukahlukene ayakwazi ukukhiqiza la ma-enzyme, kanye nama-bacteria e-heterotrophic, okuyi-Bacillus subtilis (PTCC #1204 (Persian Type Culture Collection), eyaziwa nangokuthi i-NCIMB #13061 (International Collection of Bacteria, Yeast, Phage, Plasmids, Plant Seeds and Plant Cell Tissue Cultures)) kanye ne-Bacillus amyloliquefaciens (PTCC #1732, NCIMB #12077), kwasetshenziswa kulolu cwaningo. Lawa mabhaktheriya akhuliswa endaweni equkethe i-meat peptone (5 g/L) kanye ne-meat extract (3 g/L), ebizwa ngokuthi umhluzi wezakhamzimba (NBR) (105443 Merck).
Ngakho-ke, kwalungiselelwa izindlela ezine zokufaka i-calcium carbonate precipitation kusetshenziswa imithombo emibili ye-calcium kanye namabhaktheriya amabili: i-calcium formate kanye ne-Bacillus subtilis (FS), i-calcium formate kanye ne-Bacillus amyloliquefaciens (FA), i-calcium acetate kanye ne-Bacillus subtilis (AS), kanye ne-calcium acetate kanye ne-Bacillus amyloliquefaciens (AA).
Engxenyeni yokuqala yomklamo wokuhlola, kwenziwa izivivinyo ukuze kutholakale inhlanganisela engcono kakhulu ezofinyelela ukukhiqizwa okuphezulu kwe-calcium carbonate. Njengoba amasampula enhlabathi ayequkethe i-calcium carbonate, isethi yezivivinyo zokuhlola zokuqala yaklanywa ukuze kulinganiswe ngokunembile i-CaCO3 ekhiqizwa yizinhlanganisela ezahlukene, futhi kwahlolwa izingxube zesisombululo se-culture medium kanye ne-calcium source. Kuyo yonke inhlanganisela yesisombululo somthombo we-calcium kanye ne-bacteria echazwe ngenhla (FS, FA, AS, kanye ne-AA), izici zokwenza ngcono (ukuhlushwa komthombo we-calcium, isikhathi sokwelapha, ukuhlushwa kwesisombululo se-bacteria okulinganiswe ngobuningi be-optical yesisombululo (OD), isilinganiso sesisombululo somthombo we-calcium kuya ku-bacteria, kanye ne-pH) kwatholakala futhi kwasetshenziswa ekuhlolweni kwe-wind tunnel yokwelashwa kwesihlabathi okuchazwe ezigabeni ezilandelayo.
Kuyo yonke inhlanganisela, kwenziwa izivivinyo ezingu-150 ukuze kufundwe umphumela wokwenyuka kwe-CaCO3 nokuhlola izici ezahlukahlukene, okungukuthi ukuhlushwa komthombo we-calcium, isikhathi sokwelapha, inani le-bacterium OD, isilinganiso sesisombululo somthombo we-calcium kuya kwebhaktheriya kanye ne-pH ngesikhathi sokushiswa kwe-aerobic kwezinto eziphilayo (Ithebula 1). Ububanzi be-pH benqubo elungiselelwe kahle bukhethwe ngokusekelwe kuma-growth curves e-Bacillus subtilis kanye ne-Bacillus amyloliquefaciens ukuze kutholakale ukukhula okusheshayo. Lokhu kuchazwa ngokuningiliziwe esigabeni seMiphumela.
Izinyathelo ezilandelayo zisetshenziswe ukulungiselela amasampula esigaba sokwenza ngcono. Isixazululo se-MICP saqala salungiswa ngokulungisa i-pH yokuqala ye-culture medium bese sivalwa ngokuzenzakalelayo ku-121 °C imizuzu eyi-15. Uhlobo lwabe selufakwa emgqonyeni womoya we-laminar futhi lwagcinwa ku-shaking incubator ku-30 ​​°C kanye no-180 rpm. Lapho i-OD yamabhaktheriya isifinyelele ezingeni elifunekayo, yaxutshwa nesisombululo somthombo we-calcium ngesilinganiso esifunekayo (Isithombe 1a). Isixazululo se-MICP savunyelwa ukusabela nokuqina ku-shaking incubator ku-220 rpm kanye no-30 °C isikhathi esifinyelele inani eliqondiwe. I-CaCO3 evuvukele yahlukaniswa ngemuva kokufakwa kwe-centrifugation ku-6000 g imizuzu emi-5 bese yomiswa ku-40 °C ukulungiselela amasampula okuhlolwa kwe-calcimeter (Isithombe 1b). Ukuna kwe-CaCO3 kwabe sekulinganiswa kusetshenziswa i-Bernard calcimeter, lapho i-CaCO3 powder isabela khona ne-1.0 N HCl (ASTM-D4373-02) ukuze ikhiqize i-CO2, futhi ivolumu yale gesi iyisilinganiso sokuqukethwe kwe-CaCO3 (Isithombe 1c). Ukuze kuguqulwe ivolumu ye-CO2 ibe okuqukethwe kwe-CaCO3, kwenziwa i-calibration curve ngokugeza i-CaCO3 powder emsulwa ene-1 N HCl bese idwetshwa ngokumelene ne-CO2 eguquliwe. Ukwakheka kanye nobumsulwa be-CaCO3 powder evuvukile kwahlolwa kusetshenziswa i-SEM imaging kanye nokuhlaziywa kwe-XRD. I-microscope ebonakalayo enokukhulisa okungu-1000 yasetshenziswa ukutadisha ukwakheka kwe-calcium carbonate ezungeze amabhaktheriya, isigaba se-calcium carbonate eyakhiwe, kanye nomsebenzi wamabhaktheriya.
I-Dejegh Basin iyindawo eyaziwayo eguguleke kakhulu eningizimu-ntshonalanga yeSifundazwe saseFars e-Iran, futhi abacwaningi baqoqa amasampula enhlabathi eguguleke ngomoya kule ndawo. Amasampula athathwe ebusweni benhlabathi ukuze kwenziwe ucwaningo. Ukuhlolwa kwezinkomba kumasampula enhlabathi kubonise ukuthi inhlabathi yayingahlelwanga kahle inhlabathi enesihlabathi enodaka futhi yahlukaniswa njenge-SP-SM ngokusho kwe-Unified Soil Classification System (USC) (Isithombe 2a). Ukuhlaziywa kwe-XRD kubonise ukuthi inhlabathi ye-Dejegh yayiqukethe kakhulu i-calcite ne-quartz (Isithombe 2b). Ngaphezu kwalokho, ukuhlaziywa kwe-EDX kubonise ukuthi nezinye izinto ezifana ne-Al, K, kanye ne-Fe nazo zazikhona ngezilinganiso ezincane.
Ukuze kulungiselelwe izindunduma zelabhorethri ukuze kuhlolwe ukuguguleka komoya, inhlabathi yachotshozwa kusukela ekuphakameni okungu-170 mm nge-funnel engu-10 mm ububanzi yaya endaweni eqinile, okwaholela ekutheni kube nendunduma evamile engu-60 mm ukuphakama kanye no-210 mm ububanzi. Ngokwemvelo, izindunduma zesihlabathi ezinobukhulu obuphansi kakhulu zakhiwa yizinqubo ze-aeolian. Ngokufanayo, isampula elungiselelwe kusetshenziswa inqubo engenhla yayinobukhulu obuphansi kakhulu, i-γ = 14.14 kN/m³, yakha ikhoni yesihlabathi ebekwe endaweni evundlile ene-engeli yokuphumula engaba ngu-29.7°.
Isixazululo se-MICP esihle kakhulu esitholwe esigabeni esidlule sifuthwe emthambekeni wendunduma ngesilinganiso sokusetshenziswa esingu-1, 2 kanye no-3 lm-2 bese amasampula agcinwa ku-incubator ku-30 ​​°C (Umfanekiso 3) izinsuku ezingu-9 (okungukuthi isikhathi esihle kakhulu sokupholisa) bese sithathwa siyohlolwa imigudu yomoya.
Kuyo yonke inqubo yokwelapha, kwalungiswa amasampula amane, elilodwa lokulinganisa okuqukethwe kwe-calcium carbonate kanye namandla obuso kusetshenziswa i-penetrometer, kanti amanye amasampula amathathu asele asetshenziswa ekuhlolweni kokuguguleka kwenhlabathi ngesivinini esihlukene kathathu. Ekuhlolweni kwemigudu yomoya, inani lokuguguleka kwenhlabathi lanqunywa ngesivinini somoya esihlukile, bese kuthi ijubane lokwephuka komkhawulo wesampula ngayinye yokwelapha linqunywe kusetshenziswa igrafu yenani lokuguguleka kwenhlabathi uma kuqhathaniswa nesivinini somoya. Ngaphezu kokuhlolwa kokuguguleka kwenhlabathi yomoya, amasampula aphathwe aqhunyiswa ngesihlabathi (okungukuthi, ukuhlolwa kokugxuma). Amasampula amabili engeziwe alungiselelwe le njongo ngamazinga okusetshenziswa angu-2 no-3 L m−2. Ukuhlolwa kokuqhunyiswa kwesihlabathi kwathatha imizuzu eyi-15 ngokushintshashintsha okungu-120 gm−1, okungaphakathi kwebanga lamanani akhethwe ezifundweni zangaphambilini ezingu-60,61,62. Ibanga eliqondile phakathi kwe-nozzle ebukhali kanye nesisekelo se-dune lalingu-800 mm, elitholakala ku-100 mm ngaphezu kwesisekelo somhubhe. Lesi sikhundla sabekwa ngendlela yokuthi cishe zonke izinhlayiya zesihlabathi ezigxumayo ziwele endundumeni.
Ukuhlolwa komhubhe womoya kwenziwe emhubheni womoya ovulekile onobude obungamamitha angu-8, ububanzi obungu-0.4 m kanye nokuphakama okungu-1 m (Isithombe 4a). Umhubhe womoya wenziwe ngamashidi ensimbi aqinisiwe futhi ungakhiqiza isivinini somoya esifinyelela ku-25 m/s. Ngaphezu kwalokho, kusetshenziselwa ukuguqula imvamisa ukulungisa imvamisa yabalandeli nokukhulisa kancane kancane imvamisa ukuze kutholakale isivinini somoya esiqondiwe. Isithombe 4b sibonisa umdwebo wesakhiwo wezindunduma zesihlabathi ezigugulwe umoya kanye nephrofayili yesivinini somoya esilinganiswe emhubheni womoya.
Okokugcina, ukuze kuqhathaniswe imiphumela yokwakheka kwe-MICP okungeyona i-urealytic okuphakanyiswe kulolu cwaningo nemiphumela yokuhlolwa kokulawula kwe-MICP ye-urealytic, amasampula e-dune nawo alungiswa futhi aphathwa ngesisombululo sebhayoloji esiqukethe i-urea, i-calcium chloride kanye ne-Sporosarcina pasteurii (njengoba i-Sporosarcina pasteurii inekhono elibalulekile lokukhiqiza i-urease63). Ubuningi be-optical besisombululo sebhaktheriya babungu-1.5, kanti amazinga e-urea kanye ne-calcium chloride ayengu-1 M (akhethiwe ngokusekelwe kumanani anconywe ezifundweni zangaphambilini36,64,65). Indawo yokukhulisa yayiqukethe umhluzi wezakhamzimba (8 g/L) kanye ne-urea (20 g/L). Isixazululo sebhaktheriya safuthwa ebusweni be-dune futhi sashiywa amahora angu-24 ukuze sinamathiselwe kubhaktheriya. Ngemva kwamahora angu-24 okunamathiselwa, kwafuthwa isixazululo sokuqinisa (i-calcium chloride kanye ne-urea). Ukuhlolwa kokulawula kwe-urealytic MICP kubizwa ngokuthi i-UMC. Okuqukethwe kwe-calcium carbonate kwamasampula enhlabathi aphathwe nge-urealytic kanye ne-non-urealytic kwatholakala ngokugezwa ngokwenqubo ephakanyiswe nguChoi et al.66.
Isithombe 5 sibonisa ama-curve okukhula kwe-Bacillus amyloliquefaciens kanye ne-Bacillus subtilis endaweni yokukhulisa izitshalo (isisombululo sezakhamzimba) enobubanzi be-pH bokuqala obungu-5 kuya ku-10. Njengoba kuboniswe esithombeni, i-Bacillus amyloliquefaciens kanye ne-Bacillus subtilis zikhule ngokushesha ku-pH 6-8 kanye no-7-9, ngokulandelana. Ngakho-ke, lolu bubanzi be-pH lwamukelwa esigabeni sokwenza ngcono.
Ama-curve okukhula ka-(a) i-Bacillus amyloliquefaciens kanye (b) ne-Bacillus subtilis kumanani ahlukene okuqala e-pH ye-medium yezakhamzimba.
Isithombe 6 sibonisa inani le-carbon dioxide ekhiqizwa ku-Bernard limemeter, emele i-calcium carbonate evuvukile (i-CaCO3). Njengoba isici esisodwa sasimisiwe kunhlanganisela ngayinye kanti ezinye izici zahlukahluka, iphuzu ngalinye kula magrafu lihambisana nomthamo omkhulu we-carbon dioxide kulolo sethi lokuhlola. Njengoba kuboniswe esithombeni, njengoba ukuhlushwa komthombo we-calcium kwanda, ukukhiqizwa kwe-calcium carbonate kwanda. Ngakho-ke, ukuhlushwa komthombo we-calcium kuthinta ngqo ukukhiqizwa kwe-calcium carbonate. Njengoba umthombo we-calcium kanye nomthombo we-carbon kufana (okungukuthi, i-calcium formate ne-calcium acetate), lapho kukhishwa ama-ion e-calcium amaningi, kwakheka i-calcium carbonate eningi (Isithombe 6a). Kumafomula e-AS kanye ne-AA, ukukhiqizwa kwe-calcium carbonate kwaqhubeka nokukhula ngesikhathi sokupholisa esikhulayo kuze kube yilapho inani lokupholisa licishe lingashintshi ngemva kwezinsuku ezingu-9. Kumafomula e-FA, izinga lokwakheka kwe-calcium carbonate lehla lapho isikhathi sokupholisa sidlula izinsuku ezingu-6. Uma kuqhathaniswa nezinye izinhlobo, i-formula FS ibonise izinga lokwakheka kwe-calcium carbonate eliphansi kakhulu ngemva kwezinsuku ezingu-3 (Isithombe 6b). Ezakhiweni ze-FA kanye ne-FS, u-70% kanye no-87% womkhiqizo we-calcium carbonate utholakale ngemva kwezinsuku ezintathu, kanti ezakhiweni ze-AA kanye ne-AS, lesi silinganiso sasingu-46% kanye no-45% kuphela, ngokulandelana. Lokhu kubonisa ukuthi ukwakheka okusekelwe ku-formic acid kunesilinganiso sokwakheka se-CaCO3 esiphezulu esigabeni sokuqala uma kuqhathaniswa nokwakheka okusekelwe ku-acetate. Kodwa-ke, izinga lokwakheka liyehla ngokuhamba kwesikhathi sokuqina. Kungaphethwa kusukela kuMfanekiso 6c ukuthi ngisho nasezilinganisweni zamagciwane ezingaphezu kwe-OD1, akukho mnikelo obalulekile ekwakhekeni kwe-calcium carbonate.
Ushintsho kumthamo we-CO2 (kanye nokuqukethwe kwe-CaCO3 okuhambisanayo) okulinganiswe yi-Bernard calcimeter njengomsebenzi (a) wokuhlushwa komthombo we-calcium, (b) isikhathi sokusetha, (c) i-OD, (d) i-pH yokuqala, (e) isilinganiso somthombo we-calcium kwisisombululo sebhaktheriya (kokwakheka ngakunye); kanye (f) nenani eliphezulu le-calcium carbonate elikhiqizwayo ngenhlanganisela ngayinye yomthombo we-calcium kanye namabhaktheriya.
Ngokuphathelene nomthelela we-pH yokuqala ye-medium, iSithombe 6d sibonisa ukuthi ku-FA kanye ne-FS, ukukhiqizwa kwe-CaCO3 kufinyelele inani eliphezulu ku-pH 7. Lokhu kuqaphela kuhambisana nezifundo zangaphambilini zokuthi ama-enzyme e-FDH azinzile kakhulu ku-pH 7-6.7. Kodwa-ke, ku-AA kanye ne-AS, imvula ye-CaCO3 yanda lapho i-pH idlula u-7. Izifundo zangaphambilini zibonise nokuthi ububanzi be-pH obuhle kakhulu bomsebenzi we-enzyme ye-CoA busukela ku-8 kuya ku-9.2-6.8. Uma kucatshangelwa ukuthi ububanzi be-pH obuhle kakhulu bomsebenzi we-enzyme ye-CoA kanye nokukhula kwe-B. amyloliquefaciens yi-(8-9.2) kanye ne-(6-8), ngokulandelana (Isithombe 5a), i-pH enhle kakhulu yokwakheka kwe-AA kulindeleke ukuthi ibe ngu-8, kanti ububanzi be-pH obubili buyahlangana. Leli qiniso liqinisekiswe yizivivinyo, njengoba kuboniswe kuSithombe 6d. Njengoba i-pH engcono kakhulu yokukhula kwe-B. subtilis ingu-7-9 (Isithombe 5b) kanye ne-pH engcono kakhulu yomsebenzi we-enzyme ye-CoA ingu-8-9.2, isivuno esiphezulu semvula ye-CaCO3 kulindeleke ukuthi sibe sebangeni le-pH elingu-8-9, okuqinisekiswa yiSithombe 6d (okungukuthi, i-pH enhle kakhulu yemvula ingu-9). Imiphumela eboniswe kuSithombe 6e ikhombisa ukuthi isilinganiso esihle kakhulu sesisombululo somthombo we-calcium kusisombululo sebhaktheriya singu-1 kuzo zombili izixazululo ze-acetate neze-formate. Ukuze kuqhathaniswe, ukusebenza kwezindlela ezahlukene (okungukuthi, i-AA, i-AS, i-FA, kanye ne-FS) kuhlolwe ngokusekelwe ekukhiqizweni okuphezulu kwe-CaCO3 ngaphansi kwezimo ezahlukene (okungukuthi, ukuhlushwa komthombo we-calcium, isikhathi sokwelapha, i-OD, isilinganiso sesisombululo somthombo we-calcium kusisombululo sebhaktheriya, kanye ne-pH yokuqala). Phakathi kwezindlela ezifundwe, i-formulation FS yayinokukhiqizwa okuphezulu kakhulu kwe-CaCO3, okwakucishe kube kathathu kune-formulation AA (Isithombe 6f). Kwenziwa izivivinyo ezine zokulawula ezingenabhaktheriya kuzo zombili imithombo ye-calcium futhi akukho manzi e-CaCO3 abonwe ngemuva kwezinsuku ezingu-30.
Izithombe ze-optical microscopy zazo zonke izinhlobo zibonise ukuthi i-vaterite kwakuyisigaba esiyinhloko lapho kwakhiwa khona i-calcium carbonate (Isithombe 7). Amakristalu e-vaterite ayeyindilinga ngesimo 69,70,71. Kwatholakala ukuthi i-calcium carbonate yayingena kumaseli ebhaktheriya ngoba ubuso bamaseli ebhaktheriya babushajelwe kabi futhi bungase busebenze njenge-adsorbent yama-divalent cations. Uma sithatha i-formulation FS njengesibonelo kulolu cwaningo, ngemva kwamahora angu-24, i-calcium carbonate yaqala ukwakheka kwamanye amaseli ebhaktheriya (Isithombe 7a), kwathi ngemva kwamahora angu-48, inani lamaseli ebhaktheriya ambozwe nge-calcium carbonate landa kakhulu. Ngaphezu kwalokho, njengoba kuboniswe ku-Figure 7b, izinhlayiya ze-vaterite nazo zazingatholakala. Ekugcineni, ngemva kwamahora angu-72, inani elikhulu lamabhaktheriya labonakala liboshwe amakristalu e-vaterite, futhi inani lezinhlayiya ze-vaterite landa kakhulu (Isithombe 7c).
Ukubonwa kwe-optical microscopy kwemvula ye-CaCO3 ezinhlakeni ze-FS ngokuhamba kwesikhathi: (a) 24, (b) 48 kanye (c) 72 h.
Ukuze kuqhutshekwe nokuphenywa kwesimo sesigaba esivuvukile, kwenziwa ukuhlaziywa kwe-X-ray diffraction (XRD) kanye ne-SEM yama-powder. Ama-XRD spectra (Isithombe 8a) kanye nama-SEM micrographs (Isithombe 8b, c) aqinisekisile ukuba khona kwamakristalu e-vaterite, njengoba ayenesimo esifana ne-lettuce futhi kwabonakala ukuxhumana phakathi kwama-vaterite peaks kanye nama-precipitate peaks.
(a) Ukuqhathaniswa kwama-spectra e-X-ray diffraction e-CaCO3 eyakhiwe kanye ne-vaterite. Ama-micrograph e-SEM e-vaterite ku-(b) 1 kHz kanye (c) nokukhulisa okungu-5.27 kHz, ngokulandelana.
Imiphumela yokuhlolwa kwemigudu yomoya iboniswe kuMfanekiso 9a, b. Kungabonakala kuMfanekiso 9a ukuthi ijubane lokuguguleka komhlabathi (TDV) wesihlabathi esingaphathwanga licishe libe ngu-4.32 m/s. Ngesilinganiso sokusetshenziswa esingu-1 l/m² (Isithombe 9a), imithambeka yemigqa yezinga lokulahlekelwa kwenhlabathi yezingxenyana ze-FA, FS, AA kanye ne-UMC icishe ifane neyezingxenyana zenhlabathi ezingaphathwanga. Lokhu kubonisa ukuthi ukwelashwa ngaleli zinga lokusetshenziswa akusebenzi futhi ngokushesha nje lapho isivinini somoya sidlula i-TDV, uqweqwe lomhlabathi oluncane luyanyamalala futhi izinga lokuguguleka kwezingxenyana zenhlabathi lifana nelezingxenyana zenhlabathi ezingaphathwanga. Imithambeka yokuguguleka kwengxenye ye-AS nayo iphansi kuneyezinye izingxenyana ezinezingxenyana eziphansi (okungukuthi i-TDV) (Isithombe 9a). Imicibisholo kuMfanekiso 9b ikhombisa ukuthi ngesivinini somoya esiphezulu esingu-25 m/s, akukho ukuguguleka okwenzeka ezingxenyana zenhlabathi eziphathwayo ngesilinganiso sokusetshenziswa esingu-2 no-3 l/m². Ngamanye amazwi, ku-FS, FA, AS kanye ne-UMC, izindunduma zazimelana kakhulu nokuguguleka komoya okubangelwa ukufakwa kwe-CaCO³ kumazinga okufaka angu-2 no-3 l/m² kunasesivinini somoya esiphezulu (okungukuthi 25 m/s). Ngakho-ke, inani le-TDV elingu-25 m/s elitholwe kulezi zivivinyo lingumkhawulo ophansi wamazinga okufaka aboniswe kuMfanekiso 9b, ngaphandle kwesimo se-AA, lapho i-TDV icishe ilingane nesivinini somhubhe womoya esiphezulu.
Ukuhlolwa kokuguguleka komoya (a) Ukwehla kwesisindo uma kuqhathaniswa nesivinini somoya (isilinganiso sokusetshenziswa 1 l/m2), (b) Isivinini sokudabuka komkhawulo uma kuqhathaniswa nesilinganiso sokusetshenziswa kanye nokwakheka (i-CA ye-calcium acetate, i-CF ye-calcium formate).
Isithombe 10 sibonisa ukuguguleka komhlabathi kwezindunduma zesihlabathi eziphathwe ngezindlela ezahlukene kanye namazinga okusetshenziswa ngemva kokuhlolwa kokubhomba kwesihlabathi kanye nemiphumela yobuningi iboniswe ku-Figure 11. Icala elingalashwanga aliboniswanga ngoba alibonisanga ukumelana futhi laguguleka ngokuphelele (ukulahlekelwa yisisindo sonke) ngesikhathi sokuhlolwa kokubhomba kwesihlabathi. Kusobala ku-Figure 11 ukuthi isampula ephathwe nge-biocomposition AA ilahlekelwe ngu-83.5% wesisindo sayo ngesilinganiso sokusetshenziswa esingu-2 l/m2 kanti wonke amanye amasampula abonise ukuguguleka okungaphansi kuka-30% ngesikhathi senqubo yokubhomba kwesihlabathi. Lapho izinga lokufaka lenyuswa laya ku-3 l/m2, wonke amasampula aphathwe alahlekelwe ngaphansi kuka-25% wesisindo sawo. Kuzo zombili amazinga okusetshenziswa, i-compound FS ibonise ukumelana okungcono kakhulu nokubhomba kwesihlabathi. Ukumelana okuphezulu nokuncane kakhulu kokubhomba kumasampula aphathwe yi-FS kanye ne-AA kungabangelwa ukuna kwe-CaCO3 okuphezulu nokuncane kakhulu (Isithombe 6f).
Imiphumela yokuqhuma kwezindunduma zesihlabathi zezingxenye ezahlukene ngesivinini sokugeleza esingu-2 no-3 l/m2 (imicibisholo ikhombisa isiqondiso somoya, iziphambano zikhombisa isiqondiso somoya esiqondile endizeni yomdwebo).
Njengoba kuboniswe kuMfanekiso 12, okuqukethwe yi-calcium carbonate kwawo wonke amafomula kwanda njengoba izinga lokufaka likhuphuka lisuka ku-1 L/m² kuya ku-3 L/m². Ngaphezu kwalokho, kuzo zonke izinga lokufaka, ifomula enokuqukethwe okuphezulu kakhulu kwe-calcium carbonate kwakuyi-FS, kulandelwe yi-FA kanye ne-UMC. Lokhu kusikisela ukuthi la mafomula angaba nokumelana okuphezulu kobuso.
Isithombe 13a sibonisa ushintsho ekumelaneni kobuso kwamasampula enhlabathi angalashwanga, alawulwayo nalashwayo alinganiswe ngokuhlolwa kwe-permeameter. Kusukela kulesi sibalo, kusobala ukuthi ukumelana kobuso kwama-formulations e-UMC, AS, FA kanye ne-FS kwanda kakhulu ngokwanda kwesilinganiso sokusetshenziswa. Kodwa-ke, ukwanda kwamandla obuso kwakuncane kakhulu ekwakhiweni kwe-AA. Njengoba kuboniswe esithombeni, ama-formulations e-FA kanye ne-FS e-MICP engabolile i-urea anokungena okungcono kobuso uma kuqhathaniswa ne-MICP ebolile i-urea. Isithombe 13b sibonisa ushintsho ku-TDV ngokumelana kobuso bomhlaba. Kusukela kulesi sibalo, kusobala ukuthi kuma-dunes anokumelana kobuso okungaphezu kwe-100 kPa, ijubane lokususa umkhawulo lizodlula ama-25 m/s. Njengoba ukumelana kobuso endaweni kungalinganiswa kalula nge-permeameter, lolu lwazi lungasiza ekulinganiseni i-TDV lapho kungekho ukuhlolwa kwemigudu yomoya, ngaleyo ndlela lusebenze njengesibonakaliso sokulawula ikhwalithi yezicelo zasensimini.
Imiphumela ye-SEM iboniswe kuMfanekiso 14. Izibalo 14a-b zibonisa izinhlayiya ezikhulisiwe zesampula yenhlabathi engakaphathwa, okubonisa ngokusobala ukuthi ihlangene futhi ayinabophisi bemvelo noma i-cementation. Isithombe 14c sibonisa i-micrograph ye-SEM yesampula yokulawula ephathwe nge-MICP ebolile yi-urea. Lesi sithombe sibonisa ukuba khona kwama-precipitate e-CaCO3 njengama-polymorphe e-calcite. Njengoba kuboniswe kuZithombe 14d-o, i-CaCO3 evundile ibopha izinhlayiya ndawonye; amakristalu e-spherical vaterite angabonakala kuma-micrographe e-SEM. Imiphumela yalolu cwaningo kanye nezifundo zangaphambilini ikhombisa ukuthi izibopho ze-CaCO3 ezakhiwe njengama-polymorphe e-vaterite nazo zinganikeza amandla afanele omshini; imiphumela yethu ikhombisa ukuthi ukumelana kobuso kuyanda ku-350 kPa futhi ijubane lokuhlukaniswa komkhawulo liyanda kusuka ku-4.32 kuya ngaphezu kwama-25 m/s. Lo mphumela uhambisana nemiphumela yezifundo zangaphambilini zokuthi i-matrix ye-MICP-precipitated CaCO3 iyi-vaterite, enamandla afanele okusebenza kanye nokumelana nokuguguleka komoya13,40 futhi ingagcina ukumelana nokuguguleka komoya okufanelekile ngisho nangemva kwezinsuku ezingu-180 zokuchayeka ezimweni zemvelo zasensimini13.
(a, b) Ama-micrograph e-SEM enhlabathi engaphathwanga, (c) Ukulawulwa kokuwohloka kwe-urea kwe-MICP, (df) Amasampula aphathwe nge-AA, (gi) Amasampula aphathwe nge-AS, (jl) Amasampula aphathwe nge-FA, kanye (mo) Amasampula aphathwe nge-FS ngesilinganiso sokusetshenziswa esingu-3 L/m2 ekukhulisweni okuhlukene.
Isibalo 14d-f sibonisa ukuthi ngemva kokwelashwa ngamakhemikhali e-AA, i-calcium carbonate yacwila ebusweni naphakathi kwezinhlayiya zesihlabathi, kuyilapho ezinye izinhlayiya zesihlabathi ezingamboziwe nazo zabonwa. Ezingxenyeni ze-AS, yize inani le-CaCO3 elakhiwe lingazange likhuphuke kakhulu (Isithombe 6f), inani lokuxhumana phakathi kwezinhlayiya zesihlabathi okubangelwa yi-CaCO3 landa kakhulu uma kuqhathaniswa namakhemikhali e-AA (Isithombe 14g-i).
Kusukela ku-Figures 14j-l kanye no-14m-o kusobala ukuthi ukusetshenziswa kwe-calcium formate njengomthombo we-calcium kuholela ekwandeni okwengeziwe kwemvula ye-CaCO3 uma kuqhathaniswa ne-AS compound, okuhambisana nokulinganiswa kwe-calcium meter ku-Figure 6f. Le CaCO3 eyengeziwe ibonakala ibekwe kakhulu ezinhlayiyeni zesihlabathi futhi ayithuthukisi ngempela ikhwalithi yokuxhumana. Lokhu kuqinisekisa ukuziphatha okubonwe ngaphambilini: naphezu komehluko enanini lemvula ye-CaCO3 (Figure 6f), amafomula amathathu (AS, FA kanye ne-FS) awahlukani kakhulu ngokusebenza kwe-anti-eolian (umoya) (Figure 11) kanye nokumelana nobuso (Figure 13a).
Ukuze kubonwe kangcono amaseli ebhaktheriya agcotshwe yi-CaCO3 kanye nokufakwa kwebhaktheriya kumakristalu avuvukele, kuthathwe ama-micrograph e-SEM okukhulisa okuphezulu futhi imiphumela iboniswe ku-Figure 15. Njengoba kuboniswe, i-calcium carbonate ivuvukele kumaseli ebhaktheriya futhi ihlinzeka ngama-nuclei adingekayo ukuze kuvuvukele lapho. Lesi sibalo sibonisa nokuxhumana okusebenzayo nokungasebenzi okubangelwa yi-CaCO3. Kungaphethwa ngokuthi noma yikuphi ukwanda kokuxhumana okungasebenzi akuholeli ekuthuthukisweni okuqhubekayo kokuziphatha kwemishini. Ngakho-ke, ukwandisa imvula ye-CaCO3 akuholeli emandleni aphezulu emishini futhi iphethini yemvula idlala indima ebalulekile. Leli phuzu lifundwe futhi emisebenzini kaTerzis noLaloui72 kanye noSoghi no-Al-Kabani45,73. Ukuze kuhlolwe kabanzi ubudlelwano phakathi kwephethini yemvula namandla emishini, kunconywa izifundo ze-MICP ezisebenzisa i-µCT imaging, okungaphezu kobubanzi balolu cwaningo (okungukuthi, ukwethula inhlanganisela ehlukene yomthombo we-calcium namabhaktheriya e-MICP engenayo i-ammonia).
I-CaCO3 ibangele izibopho ezisebenzayo nezingasebenzi kumasampula aphathwe ngo-(a) ukwakheka kwe-AS kanye (b) ukwakheka kwe-FS futhi yashiya uphawu lwamaseli ebhaktheriya odakeni.
Njengoba kuboniswe kuZithombe 14j-o no-15b, kukhona ifilimu ye-CaCO (ngokusho kokuhlaziywa kwe-EDX, ukwakheka kwephesenti lesakhi ngasinye kufilimu yi-carbon 11%, i-oxygen 46.62% kanye ne-calcium 42.39%, okusondele kakhulu kuphesenti le-CaCO kuSithombe 16). Le filimu imboza amakristalu e-vaterite kanye nezinhlayiya zomhlabathi, okusiza ukugcina ubuqotho besistimu yenhlabathi-sediment. Ukuba khona kwale filimu kubonwe kuphela kumasampula aphathwe ngefomula esekelwe ku-formate.
Ithebula 2 liqhathanisa amandla obuso, ijubane lokuhlukaniswa komkhawulo, kanye nokuqukethwe kwe-CaCO3 okubangelwa yi-bioinduced yenhlabathi ephathwe ngezindlela ze-MICP ezibolayo ze-urea kanye nezingabolayo ze-urea ezifundweni zangaphambilini nakulolu cwaningo. Izifundo mayelana nokumelana nokuguguleka komoya kwamasampula e-dune aphathwe nge-MICP zilinganiselwe. UMeng nabanye bahlole ukumelana nokuguguleka komoya kwamasampula e-dune aphethwe yi-urea aphethwe yi-MICP besebenzisa umshini wokuvula amaqabunga,13 kanti kulolu cwaningo, amasampula e-dune angonakalisi i-urea (kanye nezilawuli ezibolayo ze-urea) ahlolwe emhubheni womoya futhi aphathwa ngezinhlanganisela ezine ezahlukene zamabhaktheriya nezinto.
Njengoba kungabonakala, ezinye izifundo zangaphambilini zicabangele amazinga aphezulu okusetshenziswa adlula ama-4 L/m213,41,74. Kubalulekile ukuqaphela ukuthi amazinga aphezulu okusetshenziswa angase angasebenzi kalula emkhakheni ngokombono wezomnotho ngenxa yezindleko ezihambisana nokuhlinzekwa kwamanzi, ukuthuthwa kanye nokusetshenziswa kwamanzi amaningi. Amazinga aphansi okusetshenziswa afana ne-1.62-2 L/m2 nawo athole amandla amahle kakhulu omhlaba afinyelela ku-190 kPa kanye ne-TDV adlula ama-25 m/s. Kulesi sifundo samanje, ama-dunes aphathwe nge-formate-based MICP ngaphandle kokubola kwe-urea athole amandla aphezulu omhlaba afana nalawo atholwe ngendlela yokubola kwe-urea ebangeni elifanayo lamazinga okusetshenziswa (okungukuthi, amasampula aphathwe nge-formate-based MICP ngaphandle kokubola kwe-urea nawo akwazile ukufeza amazinga afanayo okusebenza njengoba kubikwe nguMeng et al., 13, Umfanekiso 13a) ngamanani aphezulu okusetshenziswa. Kungabonakala futhi ukuthi ngesilinganiso sokusetshenziswa esingu-2 L/m2, isivuno se-calcium carbonate sokunciphisa ukuguguleka komoya ngesivinini somoya esingu-25 m/s sasingu-2.25% se-MICP esekelwe ku-formate ngaphandle kokuwohloka kwe-urea, okusondele kakhulu enanini elidingekayo le-CaCO3 (okungukuthi 2.41%) uma kuqhathaniswa nezindunduma eziphathwe nge-MICP yokulawula ngokuwohloka kwe-urea ngesilinganiso sokusetshenziswa esifanayo kanye nesivinini somoya esifanayo (25 m/s).
Ngakho-ke, kungaphethwa kuleli thebula ukuthi kokubili indlela yokuwohloka kwe-urea kanye nendlela yokuwohloka engena-urea kunganikeza ukusebenza okwamukelekayo ngokwemigomo yokumelana nomphezulu kanye ne-TDV. Umehluko omkhulu ukuthi indlela yokuwohloka engena-urea ayinayo i-ammonia ngakho-ke inomthelela ophansi kwezemvelo. Ngaphezu kwalokho, indlela ye-MICP esekelwe kwi-formate ngaphandle kokuwohloka kwe-urea ephakanyisiwe kulolu cwaningo ibonakala isebenza kangcono kunendlela ye-MICP esekelwe kwi-acetate ngaphandle kokuwohloka kwe-urea. Nakuba uMohebbi nabanye bafunde indlela ye-MICP esekelwe kwi-acetate ngaphandle kokuwohloka kwe-urea, ucwaningo lwabo luhlanganise amasampula ezindaweni ezisicaba9. Ngenxa yezinga eliphezulu lokuwohloka okubangelwa ukwakheka kwe-eddy ezungeze amasampula e-dune kanye nokucheba okubangelwayo, okuholela ku-TDV ephansi, ukuwohloka komoya kwamasampula e-dune kulindeleke ukuthi kube sobala kakhulu kunokwezindawo ezisicaba ngesivinini esifanayo.