趙珂， 丁滿， 化黨領(lǐng)， 高巍， 楊秋云， 王代長， 劉世亮

(河南農(nóng)業(yè)大學(xué)資源與環(huán)境學(xué)院，450002，鄭州)

?

褐煤基改良劑對石灰性土壤復(fù)合體鉛賦存形態(tài)的影響

趙珂， 丁滿， 化黨領(lǐng)?， 高巍， 楊秋云， 王代長， 劉世亮

(河南農(nóng)業(yè)大學(xué)資源與環(huán)境學(xué)院，450002，鄭州)

摘要：為了解褐煤基材料對土壤復(fù)合體鉛形態(tài)的影響和污染退化修復(fù)機制，將褐煤以及褐煤基改性材料，混入鉛污染的土壤中培養(yǎng)4個月，提取其中的土壤復(fù)合體，測定各組復(fù)合體中的各形態(tài)鉛。結(jié)果表明：施用褐煤基有機材料后，水穩(wěn)性復(fù)合體增加。1)6種鉛化學(xué)形態(tài)在各復(fù)合體中分布狀況不同。各改良劑處理的離子交換態(tài)、鐵錳氧化物結(jié)合態(tài)和碳酸鹽結(jié)合態(tài)鉛在復(fù)合體中分布的大小順序均為：G0>G1>G2，各處理從G0到G1，交換態(tài)鉛質(zhì)量分?jǐn)?shù)下降了8.74%～32.22%，從G1到G2各處理下降了2.73%～26.74%；弱有機態(tài)和強有機態(tài)、殘渣態(tài)鉛分布順序為：G0

關(guān)鍵詞：褐煤基改良劑； 土壤修復(fù)； 鉛形態(tài)； 膠散復(fù)合體； 石灰性土壤

環(huán)境污染導(dǎo)致的土壤退化是目前影響土壤環(huán)境質(zhì)量的重要表現(xiàn)。重金屬污染的所有修復(fù)方法中，土壤改良劑對于穩(wěn)定或活化重金屬，以便降低土壤污染等級是一種有效手段。土壤有機質(zhì)積極調(diào)控著土壤的物理、化學(xué)和生物學(xué)過程[1]。褐煤與一般生物性修復(fù)材料相比，其有機部分抵抗微生物分解的能力強，其與金屬離子形成的絡(luò)合或螯合物在土壤中也更穩(wěn)定。褐煤含氧量很高，這些氧存在于羧基和羥基里，是離子交換的活性點[2-3]。褐煤是一種儲量非常豐富的富含天然腐植酸類物質(zhì)，含有羧基、醌基、羰基和甲氧基等活性基團，是一種良好的天然有機離子交換劑，具有優(yōu)異的吸附性能，用于土壤重金屬污染修復(fù)潛力巨大。長期以來，腐植酸被用于廢水處理移去有毒離子[4-5]，氫氧化鈣改性褐煤[6]可從水中高效移去重金屬Pb2+、Cd2+、Cu2+。磺化褐煤是溶液中吸附Cr6+的高效吸附劑[7]，經(jīng)磺化或堿化處理，對重金屬離子的吸附速率、吸附性能和吸附容量均有顯著改善[8]。褐煤對多離子復(fù)合污染是一種廉價吸附材料[9]，可不需進一步化學(xué)處理即具有較高的吸附能力和經(jīng)濟性，尤其高效吸附毒性離子鉛和鎘[10]。褐煤使土壤中可被植物吸收的重金屬形態(tài)下降，植物體吸收量顯著下降[11]，能夠穩(wěn)定化酸性沙土中的Pb[12]。國內(nèi)外目前多是研究了褐煤對污水中重金屬的吸附去除效果，而直接用于土壤重金屬修復(fù)研究的不多；石灰性土壤膠散復(fù)合體中重金屬形態(tài)的研究資料未見報道；根據(jù)實驗室溶液吸附試驗得到的結(jié)論，不能原封不動地用于指導(dǎo)土壤重金屬修復(fù)；直接用褐煤改良土壤，造成其氮質(zhì)量分?jǐn)?shù)低、C/N比高和酸性大等不良影響。因此，將褐煤進行改性后，施入重金屬污染土中，研究褐煤基材料對土壤不同復(fù)合體中重金屬形態(tài)改變的影響，評價褐煤基材料對重金屬活化或鈍化的效果，以便篩選和生產(chǎn)高效改良劑，為修復(fù)污染退化土壤提供理論支持。

1材料與方法

1.1供試土壤

供試土壤為河南省濟源市西北郊克井鎮(zhèn)青多村某鉛冶煉企業(yè)周圍200 m處、多重金屬重度污染的0～20 cm原位土壤，土壤類型為黃土母質(zhì)發(fā)育的褐土，質(zhì)地為黏壤質(zhì)，1～0.25 mm粗砂粒占比甚微，0.25～0.05 mm細(xì)砂粒質(zhì)量分?jǐn)?shù)低，0.05～0.001 mm間的粉粒和粗黏粒質(zhì)量分?jǐn)?shù)為56.50%，小于0.001 mm的細(xì)黏粒占39.80%。土壤pH值為8.05，有機質(zhì)、速效磷、速效鉀、堿解氮、全鉛和全鎘的質(zhì)量分?jǐn)?shù)分別為27.13、28.45、145.30、190.65、1985.76和29.35 mg/kg。

1.2試驗方法

選取云南昭通褐煤進行改性。試驗共設(shè)鈣化褐煤[13]、磺化褐煤[8]、堿化褐煤[8]、硝化褐煤[14]、褐煤制活化碳[15]、去礦化褐煤[16]、褐煤制腐殖酸[17]和堿溶酸析法等8個改良劑處理和1個原污染土為對照。每個處理用塑料盆裝土500 g，重復(fù)3次。根據(jù)先行開展的生菜盆栽試驗效果，確定土壤中添加3%的褐煤基改性材料，與土壤混合均勻培養(yǎng)，為與野外溫度接近，培養(yǎng)的溫度條件為9—12月期間的自然室溫，水分條件用稱量法控制相對含水量為75%。120 d后，每個處理取土40.00 g風(fēng)干，過20目篩，按膠散法[18]提取3組復(fù)合體(膠散復(fù)合體為小于10 μm的膠體顆粒，第1組是水分散復(fù)合體G0，第2組是鈉質(zhì)分散復(fù)合體G1，第3組是鈉質(zhì)研磨分散復(fù)合體G2)。

鉛形態(tài)分級及測定分析方法：分級采用Tessier連續(xù)提取法[19]，火焰原子吸收分光光度計測定；土壤其他理化性質(zhì)測定參考魯如坤方法[20]。采用Microsoft Excel 2007、SPSS 20.0和GraphPad Prism 5.0對所得數(shù)據(jù)進行處理分析，方差分析采用Duncan新復(fù)極差法。

2結(jié)果與分析

2.1不同改良劑處理土壤膠散復(fù)合體的質(zhì)量分?jǐn)?shù)

由表1可知，未加8種有機改良劑前，原土中非水穩(wěn)性復(fù)合體G0組在土壤中質(zhì)量分?jǐn)?shù)最高，其次是去礦化。添加褐煤基改良劑后，G1組和G2組復(fù)合體質(zhì)量分?jǐn)?shù)以腐植酸、褐煤、硝化褐煤和磺化褐煤的處理較活性炭等其他處理高。土壤中的非水穩(wěn)性G0組復(fù)合體向水穩(wěn)性G1組和G2組復(fù)合體轉(zhuǎn)化，這對于土壤理化性質(zhì)、土壤穩(wěn)定團聚體和重金屬的賦存狀態(tài)具有重要影響，有利于提高土壤抗侵蝕能力。

表1　土壤各膠散復(fù)合體的質(zhì)量分?jǐn)?shù)

注：G0為水分散復(fù)合體，G1為鈉質(zhì)分散復(fù)合體，G2為鈉質(zhì)研磨分散復(fù)合體。分別對同組復(fù)合體不同處理的鉛形態(tài)含量作方差分析與多重比較，P<0.05。下同。Note: G0named as water-dispersing complex, G1as NaCl-dispersing complex, G2as NaCl-grinding-dispersing complex. Variance analysis and multiple comparison of content of different lead chemical speciation in the same group of complexes with different treatments atP<0.05. The same as below.

2.2對土壤膠散復(fù)合體中鉛形態(tài)的影響

2.2.1離子交換態(tài)鉛圖1示出，從G0到G1，各處理交換態(tài)鉛質(zhì)量分?jǐn)?shù)下降了8.74%～32.22%，G1到G2各處理下降了2.73%～26.74%。即交換態(tài)離子主要存在于非水穩(wěn)性G0組有機無機復(fù)合體中，G1和G2作為不易變化的復(fù)合體形態(tài)，其易交換態(tài)鉛質(zhì)量分?jǐn)?shù)也隨之下降。各處理的交換態(tài)質(zhì)量分?jǐn)?shù)比較，G0組復(fù)合體中，堿化、鈣化、腐植酸和活性炭處理的離子交換態(tài)鉛質(zhì)量分?jǐn)?shù)顯著下降，而褐煤、硝化、去礦化和磺化對交換態(tài)鉛的影響較小。G1組和G2組復(fù)合體中，各處理的離子交換態(tài)鉛質(zhì)量分?jǐn)?shù)均有所下降，以褐煤和活性炭下降最多。改性與未改性的褐煤相比，堿化、鈣化、腐植酸和活性炭顯著降低G0組中交換態(tài)鉛的質(zhì)量分?jǐn)?shù)，G1組中，改性材料引起的交換態(tài)鉛大致有升高趨勢，以去礦化和磺化達(dá)到了顯著性升高。G2組中，改性后導(dǎo)致的交換態(tài)質(zhì)量分?jǐn)?shù)都顯著高于改性前的褐煤。

圖1　G0、G1和G2復(fù)合體的離子交換態(tài)鉛變化Fig.1　Content of ion-exchangeable Pb in complexes fo G0, G1 and G2

2.2.2碳酸鹽結(jié)合態(tài)鉛圖2示出，3組復(fù)合體的碳酸鹽結(jié)合態(tài)鉛質(zhì)量分?jǐn)?shù)、腐植酸和褐煤處理比原土顯著降低。腐植酸處理的G0、G1、G2組復(fù)合體的碳酸鹽結(jié)合態(tài)鉛質(zhì)量分?jǐn)?shù)分別比原土低12.25%，12.38%，15.17%。與未改性褐煤比較，除腐植酸使碳酸鹽態(tài)鉛降低外，其他改性均使3組復(fù)合體中碳酸鹽態(tài)鉛質(zhì)量分?jǐn)?shù)升高，但都未達(dá)顯著差異，碳酸鹽態(tài)鉛在3組復(fù)合體中的質(zhì)量分?jǐn)?shù)差異不大。

圖2　G0、G1和G2復(fù)合體的碳酸鹽結(jié)合態(tài)鉛變化Fig.2　Content of carbonate-bound Pb in complexes of G0, G1 and G2

2.2.3鐵錳氧化物結(jié)合態(tài)鉛圖3示出，同組復(fù)合體各處理與原土比較，3組均未達(dá)到顯著性差異，但G1和G2組中，腐植酸明顯降低了鐵錳氧化物態(tài)質(zhì)量分?jǐn)?shù)，其他改性處理多為升高。與褐煤相比，G1組堿化和鈣化顯著提高了鐵錳氧化物質(zhì)量分?jǐn)?shù)，G0和G2組各改性與褐煤比無顯著性差異。3組復(fù)合體中鐵錳氧化物質(zhì)量分?jǐn)?shù)比較，各材料處理均表現(xiàn)為G0>G1>G2，均值分別為1 324.89、1 287.58和1 263.58 mg/kg。

圖3　G0、G1和G2復(fù)合體的鐵錳氧化物結(jié)合態(tài)鉛變化Fig.3　Content of Fe-Mn-oxide-bound Pb in complexes fo G0,G1 and G2

圖4　G0、G1和G2復(fù)合體的弱有機結(jié)合態(tài)鉛變化Fig.4　Content of organics-weakly-bound Pb in complexes of G0,G1 and G2

圖5　G0、G1和G2復(fù)合體的強有機結(jié)合態(tài)鉛變化Fig.5　Content of organics-strongly-bound Pb in complexes of G0, G1 and G2

2.2.4弱有機結(jié)合態(tài)鉛圖4示出，從G0到G1到G2，各處理的弱有機態(tài)鉛質(zhì)量分?jǐn)?shù)都明顯增加，G0到G1的增加幅度為6.89%～48.48%，G1到G2為5.70%～26.18%。說明弱有機態(tài)在相對穩(wěn)定的G1和G2組復(fù)合體中質(zhì)量分?jǐn)?shù)較多。各處理比較，G0組各處理的弱有機態(tài)鉛質(zhì)量分?jǐn)?shù)未達(dá)到顯著性差異；G1和G2組的褐煤、腐植酸、硝化和磺化顯著高于原土，G1組這4種材料分別比原土高了51.23%、47.35%、35.06%和44.59%，G2組分別高了41.35%、40.03%、32.95%和27.11%。改性后堿化、鈣化、去礦化和活性炭顯著降低了弱有機態(tài)鉛的質(zhì)量分?jǐn)?shù)，而腐植酸、硝化和磺化與改性前無顯著影響。

2.2.5強有機結(jié)合態(tài)鉛圖5示出，從G0到G1到G2，強有機態(tài)鉛質(zhì)量分?jǐn)?shù)逐漸增加。增加幅度從G0到G1平均為24%，從G1到G2平均為6.27%。說明在穩(wěn)定性復(fù)合體中，強有機態(tài)鉛賦存較多。G0組復(fù)合體中，褐煤、硝化和腐植酸處理的強有機態(tài)鉛質(zhì)量分?jǐn)?shù)顯著增加，8種材料的提高幅度為5.44%～38.29%；G1組中提高了1.95%～62.23%，褐煤和腐植酸處理的強有機態(tài)鉛質(zhì)量分?jǐn)?shù)分別提高了42.47%和36.95%；G2組中提高了2.51%～67.65%，褐煤和腐植酸處理比原土分別提高62.23%和67.65%。褐煤改性后，多數(shù)降低了強有機態(tài)鉛質(zhì)量分?jǐn)?shù)。

2.2.6殘渣態(tài)鉛圖6示出，3組復(fù)合體中，各處理的殘渣態(tài)鉛質(zhì)量分?jǐn)?shù)均與原土無顯著性差異。G0組中，堿化和鈣化比褐煤顯著降低了殘渣態(tài)鉛質(zhì)量分?jǐn)?shù)，分別低了15%和17%。G1和G2組中，殘渣態(tài)鉛各處理均未達(dá)到顯著性差異。G0、G1和G2中的各處理殘渣態(tài)鉛范圍分別為318.51～381.82、352.73～451.40和333.15～441.21 mg/kg。說明殘渣態(tài)鉛在穩(wěn)定性復(fù)合體G1和G2中賦存質(zhì)量分?jǐn)?shù)高于G0中，褐煤基有機材料對殘渣態(tài)鉛的影響不顯著或具有不確定性。

圖6　G0、G1和G2復(fù)合體的殘渣態(tài)鉛變化Fig.6　Content of residual Pb in complexes of G0, G1 and G2

3結(jié)論與討論

1) 施入有機材料后，提高了水穩(wěn)性復(fù)合體在土壤中的質(zhì)量分?jǐn)?shù)，腐植酸、褐煤、硝化褐煤和磺化褐煤形成更多的水穩(wěn)性復(fù)合體，腐植酸處理形成的水穩(wěn)性G1和G2組最多，有利于穩(wěn)定土壤結(jié)構(gòu)和提高抗侵蝕力。交換態(tài)、鐵錳氧化物態(tài)鉛和碳酸鹽態(tài)鉛主要賦存于非水穩(wěn)性復(fù)合體中，強、弱有機態(tài)鉛和殘渣態(tài)鉛主要存在于水穩(wěn)性復(fù)合體中。穩(wěn)定復(fù)合體和團聚體形成后，能夠穩(wěn)定土壤結(jié)構(gòu)，增強對重金屬的固定或鈍化能力，提高土壤抗侵蝕，并降低重金屬溶解、淋溶和環(huán)境風(fēng)險。

2) 有機材料均引起了3組復(fù)合體中交換態(tài)鉛質(zhì)量分?jǐn)?shù)的下降，普遍提高強有機態(tài)鉛質(zhì)量分?jǐn)?shù)，部分材料提高了弱有機態(tài)鉛質(zhì)量分?jǐn)?shù)，表現(xiàn)出褐煤基有機材料對鉛的顯著鈍化作用，但對殘渣態(tài)和鐵錳氧化物態(tài)鉛沒有顯著影響。其材料可以作為鉛污染退化土壤的有效修復(fù)劑?？山粨Q態(tài)、碳酸鹽態(tài)、Fe/Mn氧化物態(tài)和有機態(tài)4種形態(tài)存在的重金屬合稱為“有效態(tài)重金屬”[20]。殘渣態(tài)重金屬在自然界正常條件下不易釋放[21]。幾種鉛形態(tài)受有機材料影響后，總的變化規(guī)律是交換態(tài)鉛顯著下降，弱有機態(tài)和強有機態(tài)主要是顯著升高，碳酸鹽鉛受到部分有機材料影響而改變，而殘渣態(tài)鉛很少受到外源有機物料的影響而改變，鐵錳氧化物態(tài)也很少改變，反映出可交換態(tài)與2種有機態(tài)的互動比較明顯。殘渣態(tài)影響較小，與文獻[21]的說法一致。然而J.Pavel等[22]認(rèn)為，施入腐植酸鉀后，鐵錳氧化物態(tài)鉛的下降和殘留態(tài)鉛的顯著增加，是由于腐植酸的酸性和其對鉛的強烈的復(fù)合能力所致。這與本文的研究結(jié)果“褐煤基有機材料對鐵錳氧化物態(tài)和殘留態(tài)鉛的影響較小”存在差異。

3) 褐煤改性后比改性前主要提高了交換態(tài)鉛和碳酸鹽態(tài)鉛質(zhì)量分?jǐn)?shù)，降低了強、弱有機態(tài)鉛質(zhì)量分?jǐn)?shù)。本文中多種改性處理，對降低或提高土壤鉛有效性等方面的影響，均可從已有研究結(jié)果如腐殖酸的結(jié)構(gòu)和元素特征[23-25]、褐煤活性炭特征[26]、褐煤去礦化后酸性特征[27-28]、硝酸改性褐煤特征[29]、荷鈣褐煤特征[9]、磺化褐煤特征[30]中獲得一定程度的理論解釋，但其準(zhǔn)確作用機制還需進一步研究。

4參考文獻

[1]李文軍，彭保發(fā)，楊奇勇.長期施肥對洞庭湖雙季稻區(qū)水稻土有機碳、氮積累及其活性的影響[J].中國農(nóng)業(yè)科學(xué)，2015，48 (3)：488.

Li Wenjun，Peng Baofa，Yang Qiyong. Effects of long-term fertilization of organic carbon and nitrogen accumulation and activity in a paddy soil in double cropping rice area in Dongting lake of China[J].Scientia Agricultura Sinica,2015,48(3)：488.(in Chinese)

[2]Lafferty C, Hobday M. The use of low rank brown coal as an exchange material[J]. Fuel, 1990, 69：78.

[3]Murakami K, Yamada T, Fuda K, et al.Selectivity in cation exchange property of heat-treated brown coals[J]. Fuel, 2001, 80：599.

[4]Ucurum M. A study of removal of Pb heavy metal ions from aqueous solution using lignite and a new cheap adsorbent (lignite washing plant tailings) [J].Fuel,2009, 88(8)：1460.

[5]Pehlivan E, Arslan G.Removal of metal ions using lignite in aqueous solution-low cost biosorbents[J]. Fuel Processing Technology,2007,88：99.

[6]Milu?e J, Miroslav P,Jan H,et al. Removal of heavy metals from water by lignite-based sorbents[J]. Fuel,2004,83：1197.

[7]Zhang Runhu, Wang Bo, Ma Hongzhu.Studies on Chromium (Ⅵ) adsorption on sulfonated lignite[J]. Desalination,2010,255：61.

[8]張懷成，王在峰，李建義，等.褐煤經(jīng)磺化及堿化處理對重金屬離子吸附性能研究[J].環(huán)境化學(xué)，1999，18(5)：482.

Zhang Huaicheng,Wang Zaifeng, LiJianyi, et al.Studies on the adsorption characteristics of lignite activated by sulphonation or alkalization for heavy-metal ions[J].Environmental Chemistry,1999,18(5)：482. (in Chinese)

[9]Leo? D,Miloslav P. Removal of metal ions from multi-component mixture using natural lignite[J].Fuel Processing Technology, 2012,101：29.

[10]Martina H, Jiri M, Ivana S, et al. Sorption of metal ions on lignite and the derived humic substances[J]. Journal of Hazardous Materials, 2009,161 ：559.

[11]Pusz A. Influence ofbrown coal on limit of phytotoxicity of soils contaminated with heavy metals[J]. Journal of Hazardous Materials, 2007,149：590.

[12]Nikolett U, Márk R, Eszter D,et al.Stabilization of Cr, Pb, and Zn in soil using lignite[J].Soil and Sediment Contamination: An International Journal,2014,23(3)：270.

[14]王魯敏,鄧昌亮,殷軍港,等.硝化褐煤對鉻離子溶液的吸附研究[J].環(huán)境化學(xué),2001,20(1)：54.

Wang Lumin, Deng Changliang, Yin Jungang, et al. Study on adsorption of nitrify lignite for chromium-ion solution[J].Environmental Chemistry,2001,20(1)：54.(in Chinese)

[15]羅道成,鄭李輝.用褐煤活化一步法制備活性炭的研究[J].煤化工,2009,37(5)：25.

Luo Daocheng, ZhengLihui. Study on the preparation of activated carbon by one-step method of carbonization-activation with lignite coal[J]. Coal Chemistry Industry,2009,37(5)：25.(in Chinese)

[17]黃金鳳,趙義龍,趙金香，等.腐植酸的提取及其成分含量測定[J].四川畜牧獸醫(yī),2007,34(5)：27.

Huang Jinfeng, Zhao Yilong, Zhao Jinxang, et al. The extraction and determination of composition of humic acid[J]. Sichuan Animal & Veterinary Science,2007,34(5)：27. (in Chinese)

[18]化黨領(lǐng),張一平.塿土不同施肥條件下土壤膠散復(fù)合體研究[J].土壤肥料,1999(1)：9.

Hua Dangling, Zhang Yipeng. Study on soil organo-mineral complex on Lou-soil[J].Soil and Fertilizer, 1999,(1)：9.(in Chinese)

[19]Tessier A, Campbell P G, Bisson M. Sequential extraction procedure for the speciation of particulate trace metals[J]. Analytical Chemistry,1979,51(7)：844.

[20]周康民,湯志云,黃光明,等.土壤中重金屬形態(tài)分析方法研究[J].江蘇地質(zhì),2007,31(3)：165.

Zhou Kangmin, Tang Zhiyun, Huang Guangming, et al. Methodology study on heavy metal morphology analysis[J]. Jiangsu Geology, 2007,31(3)：165. (in Chinese)

[21]李宇慶，陳玲，仇雁翎，等．上海化學(xué)工業(yè)區(qū)土壤重屬元素形態(tài)分析[J]．生態(tài)環(huán)境，2004，13(2)：154.

Li Yuqing, Chen Ling, Qiu Yanling, et al. Speciation of heavy metals in soil from Shanghai Chemical Industry Park[J]. Ecology and Environment, 2004, 13(2)：154. (in Chinese)

[22]Pavel J, Jana V, Lucie H,et al.Effects of inorganic and organic amendments on the mobility (leachability) of heavy metals in contaminated soil: A sequential extraction study[J].Geoderma, 2010,159：335.

[23]喻偉.伊敏褐煤腐殖酸結(jié)構(gòu)特征及熱解動力學(xué)分析[J].科技創(chuàng)新與生產(chǎn)力，2011(6)：94.

Yu Wei. Analysis on features of humus acid texture of lignite coal and pyrolysis dynamics[J]. Sci-Tech Innovation & Productivity, 2011(6)：94. (in Chinese)

[24]Martyniuk H, Wieckowska J. Adsorption of metal ions on humic acids extracted from brown coals[J]. Fuel Process Technology, 2003,84(1/2/3)：23.

[25]Clemente R, Bernal M P. Fractionation of heavy metals and distribution of organic carbon in two contaminated soils amended with humic acid[J]. Chemosphere, 2006,64(8)：1264.

[26]陳雯，劉中華，范艷青，等.褐煤活性炭的制備與性能研究[J].煤炭轉(zhuǎn)化，2004，27(2)：61.

Chen Wen, Liu Zhonghua, Fan Yanqing, et al. Study on preparation and properties of activated carbon from lignite[J]. Coal Conversion, 2004,27(2)：61. (in Chinese)

[27]Hadi Z, Nursen O, Mehtap G, et al. Images of demineralized coal surfaces by scanning tunnelling microscopy[J]. Fuel,1996,75(7)：855.

[28]Julien S, Philippe B, Sebastien M, et al. The influence of demineralisation and ammoxidationon: the adsorption properties of an activated carbon prepared from a Polish lignite[J]. Carbon,2006,44：2549.

[29]上官炬，楊直，苗茂謙. 硝酸改性褐煤半焦制備煙氣脫硫劑[J].太原理工大學(xué)學(xué)報，2007，38(3)：229.

Shangguan Ju, Yang Zhi, Miao Maoqian. The SO2adsorbent prepared by the oxidation with HNO3from lignite semi coke[J]. Journal of Taiyuan University of Technology,2007,38(3)：229. (in Chinese)

[30]Halina M, Danuta A.Sorption of metal cations on sulphonated brown coals[J].Fuel,1991,70(4)：551.

(責(zé)任編輯：程云郭雪芳)

Effects of lignite-based amendments on lead chemical speciation in calcareous soil organo-mineral complexes

Zhao Ke, Ding Man, Hua Dangling, Gao Wei, Yang Qiuyun, Wang Daichang, Liu Shiliang

(College of Resources and Environment, Henan Agricultural University, 450002, Zhengzhou, China)

Abstract:[Background] In order to remediate heavy metal-contaminated calcareous soil, a comparative research on the effect of lignite-based materials on heavy metals speciation of different organo-mineral complexes were conducted for screening out highly effective amendments and understanding the restoration mechanism of pollution degradation. [Methods] All these materials were mixed with lead-contaminated soiland incubated for 120 days at 25 ℃ and 65% relative humidity, thereafter organo-mineral complexes were extracted, and mass fraction of different Pb chemical speciation of soil complexes were assessed. [Results] The results indicated that water-stable complexes were increased with the application of lignite organic materials,the treatments with humic acid,lignite,nitrified lignite and sulphonated lignite transformed more of G1 and G2 complexes from G0, and other results were as follows:1) The distributions of 6 Pb chemical speciation (ion-exchangeable Pb, Fe-Mn-oxide-bound Pb, carbonate-bound Pb, organics-weakly-bound Pb, organics-strongly-bound Pb, and residual Pb) varied in the different complexes G0 (water-dispersing complex), G1(NaCl-dispersing complex),and G2(NaCl-grinding-dispersing complex). For all amendments, the order of the abundance for ion-exchangeable Pb, Fe-Mn-oxide-bound Pb, and carbonate-bound Pbwas G0>G1>G2; the ion-exchangeable Pb decreased 8.74%-32.22% from G0 to G1, and 2.73%-26.74% from G1 to G2; organics-weakly-bound Pb, organics-strongly-bound Pb, and residual Pb in G1 and G2 complexes were more than that in G0. 2) Applying organic materials decreased the content of ion-exchangeable Pb averagely 2.73%-32.22%in 3 complexes, while increased the organics-weakly-bound Pb at a maximum of 51.23% and organics-strongly-bound Pb at a maximum of 67.65%, no significant effect on residual Pb. Organics-weakly-bound Pb in G0 was less significantly affected than that in G1 and G2 by these organic materials, and the content of organics-weakly-bound Pb in G1 complexes treated with lignite, humic acid, nitrified lignite and sulphonated lignite were higher than original soil in the range of 35.06%-51.23%, and in G2 higher in the range of 27.11%-41.35%. All lignite-based materials increased the content of organics-strongly-bound Pb in the range of 5.44%-38.29%, but had no significant effect on residual Pb of G0, G1 and G2. 3) Compared with raw lignite, the treatments with humic acid, active charcoal, alkalization and calcium-loaded lignite decreased markedly the content of ion-exchangeable Pb in G0 group, but all modified lignite increased ion-exchangeable Pb content in G2 group, as well as sulphonation and demineralization increased ion-exchangeable Pb in G1 remarkably. Except humic acid,many modified lignite-based materials resulted in lower content of organics-strongly-bound Pb in all three groups of complex.There were no significant differences on content of carbonate-bound Pb in all complexes between original and modified lignite.Alkalization and calcium-loaded lignite markedly decreased residual Pb in G0, and the same changes in G1 and G2. Simultaneously, alkalization and calcium-loaded lignite increased significantly Fe-Mn-oxide-bound Pb in G1. [Conclusions] In conclusion, applying lignite-based amendments is effective in increasing water-stable complexes and prompting more organically-bound Pb speciation in contaminated soil, decreasing the fraction of ion-exchangeable Pb, thus it helps establish stable soil structure, enhance the capacity of resisting soil erosion, and decrease the environmental exposure risk by surface runoff and deep percolation. Organic lignite-based amendments improve remarkably content of organically-bound Pb, nevertheless, organic matter has little effect on Fe-Mn-oxide-bound, residual and carbonate-bound Pb. Taking immobilization and economy efficiency into account, raw lignite, humic acid, active charaoal, nitrified lignite and sulphonated lignite are recommended for remediating Pb-contaminated soil.

Keywords:lignite-based amendments; soil remediation; lead chemical speciation; organo-mineral complex; calcareous soil

收稿日期：2015-07-23修回日期： 2016-01-04

第一作者簡介：趙珂(1988—)，女，碩士研究生。主要研究方向：土壤重金屬污染修復(fù)。E-mail: 1060048917@qq.com ?通信 化黨領(lǐng)(1964—)，男，博士，教授。主要研究方向：土壤學(xué)與植物營養(yǎng)學(xué)。E-mail: collegehua@163.ocm

中圖分類號：S156.2

文獻標(biāo)志碼：A

文章編號：1672-3007(2016)01-0123-08

DOI:10.16843/j.sswc.2016.01.015

項目名稱： 國家自然科學(xué)基金“褐煤基改性材料轉(zhuǎn)化石灰性土壤重金屬形態(tài)的機理和其對重金屬時空變異的影響”(41371311)，“硫素對稻根表面鐵錳膠膜形成及水稻吸收Cd和As有效性的影響”(41271471)