陳明翔，周集體，路達(dá),2，張玉

(1.大連理工大學(xué) 環(huán)境學(xué)院,工業(yè)生態(tài)與環(huán)境工程教育部重點(diǎn)實(shí)驗(yàn)室，遼寧 大連 116024； 2.河北大學(xué) 化學(xué)與環(huán)境科學(xué)學(xué)院,河北 保定 071002)

隨著工業(yè)的發(fā)展，化石燃料的大量燃燒所產(chǎn)生的二氧化硫(SO2)和一氧化氮(NO)，造成了酸雨、臭氧層破壞、光化學(xué)煙霧等環(huán)境污染，并嚴(yán)重威脅人類的健康[1].SO2和NO一體化脫除技術(shù)，作為大氣污染治理的發(fā)展趨勢(shì)之一，已經(jīng)得到廣泛研究[2-3].目前，比較常見(jiàn)的煙氣同時(shí)脫硫脫硝技術(shù)主要包括等離子體法、液相氧化法、光催化氧化法、絡(luò)合吸收法、吸附法等[4-8].盡管這些方法有著諸多的優(yōu)點(diǎn)，但仍有許多方面需要改進(jìn)，如高能耗、高成本、存在二次污染等問(wèn)題.生物法工業(yè)廢氣凈化技術(shù)因其設(shè)備簡(jiǎn)單、投資及運(yùn)行費(fèi)用低、且無(wú)二次污染等優(yōu)點(diǎn)日益受到人們的關(guān)注[1].目前，多數(shù)研究采用生物法單獨(dú)脫除SO2或NO，而生物法同步脫硫脫硝尚處于實(shí)驗(yàn)探索階段[3].

1 材料和方法

1.1 菌種

實(shí)驗(yàn)采用的SRB是由大連市春柳河污水處理廠的厭氧污泥經(jīng)富集、馴化、反復(fù)稀釋涂布而得.經(jīng)16S rDNA測(cè)序和Blast分析表明，菌株與脫硫弧菌屬(Desulfovibriosp.)的同源性最高，故命名為Desulfovibriosp.CMX.在GenBank上登錄，其序列號(hào)為GU584224.在廣東省微生物菌種保藏中心的保藏號(hào)為GIM1.765.

1.2 培養(yǎng)基

富集培養(yǎng)基：K2HPO4,0.50 g；NH4Cl,1.00 g；MgSO4·7H2O,2.00 g；Na2SO4,0.86 g；CaCl2,0.10 g；酵母浸粉，1.00 g；乳酸鈉(質(zhì)量分?jǐn)?shù)為70%～80%)，5 mL；蒸餾水，1 000 mL，pH值調(diào)至7.00±0.20.在0.1 MPa，121 ℃下滅菌20 min.在培養(yǎng)基使用前用濾膜過(guò)濾滅菌加入0.10 g的維生素C.

基礎(chǔ)培養(yǎng)基：Na2HPO4·12H2O，5.00 g；NaH2PO4·2H2O，2.20 g；酵母浸粉，1.00 g；乳酸鈉(質(zhì)量分?jǐn)?shù)為70%～80%)，5 mL；蒸餾水，1 000 mL.在0.1 MPa，121 ℃下滅菌20 min.在培養(yǎng)基使用前用濾膜過(guò)濾滅菌加入0.10 g的維生素C.

1.3 菌株脫硫性能的優(yōu)化

1.3.1 pH值對(duì)D.sp.CMX的脫硫性能的影響

1.3.2 不同碳源對(duì)D.sp.CMX脫硫性能的影響

1.4 菌株Fe(Ⅲ)EDTA還原能力的考察

分別將0，5，15，25 mmol/L的Fe(Ⅲ)EDTA加入100 mL基礎(chǔ)培養(yǎng)基中，并將D.sp.CMX(細(xì)胞蛋白質(zhì)量濃度為20.00 mg/L)分別厭氧接種于初始Fe(Ⅲ)EDTA濃度不同的培養(yǎng)基中，在pH=7、溫度為30 ℃的條件下厭氧培養(yǎng)，并定期取樣測(cè)定其蛋白生長(zhǎng)量、亞鐵(Fe2+)和總鐵含量.

1.5 分析方法

2 結(jié)果和討論

2.1 pH對(duì)D.sp.CMX的脫硫性能的影響

圖1 pH值不同時(shí)D.sp.CMX的脫硫性能Fig.1 Sulfate reducing performances of D.sp.CMX at different pH values

圖2 不同碳源時(shí)D.sp.CMX的脫硫性能Fig.2 Sulfate reducing performances of D.sp.CMX at different carbon sources

2.2 碳源對(duì)D.sp.CMX的脫硫性能的影響

2.3 初始質(zhì)量濃度對(duì)D.sp.CMX的脫硫性能的影響

ρ/(g·L-1)圖3 初始的質(zhì)量濃度不同時(shí)D.sp.CMX的脫硫性能Fig.3 Sulfate reducing performances of D.sp.CMX at different sulfate concentrations

2.4 D.sp.CMX的鐵還原能力的考察

圖4 D.sp.CMX的鐵還原能力Fig.4 Ferric reducing capacity of D.sp.CMX

圖5 D.sp.CMX在Fe(Ⅲ)EDTA中的生長(zhǎng)情況Fig.5 Growth of D.sp.CMX in Fe(Ⅲ)EDTA solution

SRB可以直接將Fe(Ⅲ)、尤其是水溶態(tài)的Fe(Ⅲ)生物還原，但是，又有研究表明，25 mmol/L的Fe(Ⅲ)EDTA不是一個(gè)合適的電子受體，大部分的異養(yǎng)鐵還原微生物無(wú)法還原25 mmol/L的Fe(Ⅲ)EDTA[23-25].而在本實(shí)驗(yàn)中，菌株D.sp.CMX在25 mmol/L的Fe(Ⅲ)EDTA溶液中，也可以發(fā)生異養(yǎng)的鐵還原.隨著Fe(Ⅲ)EDTA濃度的升高，D.sp.CMX在22 h時(shí)的蛋白濃度反而降低，這可能是由絡(luò)合劑對(duì)SRB的毒性導(dǎo)致的，已有研究證明，EDTA、檸檬酸都對(duì)SRB的活性有一定的抑制作用[26].

3 結(jié)論

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