Adsorption and transport of uranium in porous sandstone media

doi:10.13745/j.esf.sf.2022.1.30

Abstract

Abstract:

After the decommissioning of a in-situ leach uranium mining site, residual uranium leaching fluid in the aquifer migrates and diffuses downstream posing pollution risks to the surrounding groundwater. In this study, a series of batch and column experiments were designed to investigate the adsorption and migration behavior of uranium in aquifer sandstone in an in-situ leach uranium mining area in northern China. In batch experiments, uranium adsorption on sandstone reached equilibrium within 12 h, and in the process a positive correlation between the initial uranium concentration and sandstone’s uranium adsorption capacity was observed. It was found that the uranium adsorption process was endothermic and the increase in temperature was beneficial for uranium adsorption. The pH of the eluent and $HCO 3 -$ concentration have a strong influence on uranium adsorption. Maximum uranium adsorption was reached at around neutral pH, and higher $HCO 3 -$ concentration led to lower level of adsorption. These effects are due to the alteration of uranium complexation in the solution and the surface charge properties of sandstone. In column experiments, pH, uranium concentration, flow rate, and $HCO 3 -$ concentration were the most important factors affecting uranium migration. Weaker acidity (pH≤7) was found to be associated with fewer late uranium breakthrough in the sandstone column; whereas higher uranium concentration, flow rate, and $HCO 3 -$ concentration might cause early uranium breakthrough. The two-point non-equilibrium model could well describe the uranium migration process in the sandstone column under variable conditions. The partition coefficients obtained from batch experiments were 1.1-6.6 fold higher than those obtained from column experiments. According to the aquifer characteristics and hydrogeochemical characteristics, we suggest that the distribution coefficient of 48.1 mL/g would be suitable for describing uranium migration in sandstone aquifers in the study area. Overall, this study provided a theoretical basis for the reactive transport process and for the natural remediation of polluted groundwater in the in-situ leaching uranium mining areas.

Key words: groundwater, uranium, Adsorption, column experiments, two-site chemical non-equilibrium model, partition coefficient

CLC Number:

X523

CUI Di, YANG Bing, GUO Huaming, LIAN Guoxi, SUN Juan. Adsorption and transport of uranium in porous sandstone media[J]. Earth Science Frontiers, 2022, 29(3): 217-226.

Figures/Tables 11

Table 1 Experimental conditions in column experiments

柱编号	pH值	铀浓度/ (mg·L^-1)	流速/ (mL·min^-1)	$HCO 3 -$ 浓度/ (mmol·L^-1)
1	4	2	0.1	0
2	7	2	0.1	0
3	8.5	2	0.1	0
4	7	1	0.1	0
5	7	5	0.1	0
6	7	2	0.5	0
7	7	2	0.3	0
8	7	2	0.1	0.5
9	7	2	0.1	1.0

Table 1 Experimental conditions in column experiments

柱编号	pH值	铀浓度/ (mg·L^-1)	流速/ (mL·min^-1)	$HCO 3 -$ 浓度/ (mmol·L^-1)
1	4	2	0.1	0
2	7	2	0.1	0
3	8.5	2	0.1	0
4	7	1	0.1	0
5	7	5	0.1	0
6	7	2	0.5	0
7	7	2	0.3	0
8	7	2	0.1	0.5
9	7	2	0.1	1.0

Table 2 Characteristic hydraulic parameters

柱号	饱和含水率θ	流速 v/(cm·min^-1)	弥散系数 D/(cm²·min^-1)	弥散度 λ/cm	R²
1	0.333	0.309	0.011	0.034	0.998
2	0.411	0.308	0.012	0.037	0.998
3	0.457	0.270	0.009	0.034	0.993
4	0.342	0.330	0.028	0.085	0.982
5	0.346	0.342	0.018	0.053	0.995
6	0.420	0.959	0.087	0.091	0.999
7	0.389	0.585	0.011	0.019	0.993
8	0.405	0.297	0.021	0.072	0.985
9	0.447	0.287	0.018	0.064	0.999

Fig.1 Temporal variation of uranium concentration in solution under different initial uranium concentrations

Table 3 Parameters of psudo first order and psudo second order kinetic models for uranium adsorption on sandstone

U初始浓度/ (mg·L^-1)	实验q'_e/ (10² mg·g^-1)	准一级动力学	准二级动力学
U初始浓度/ (mg·L^-1)	实验q'_e/ (10² mg·g^-1)	R²	q_e/(10² mg·g^-1)	k₂/(g·mg^-1·h^-1)	R²
1	2.763	0.237	2.794	69.973	0.997
2	5.268	0.443	5.357	24.928	0.993
5	22.555	0.338	22.367	12.562	0.999

Table 4 Langmuir and Freundlich constants for uranium adsorption on sandstone at different temperatures

温度/℃	Langmuir等温吸附方程			Freundlich等温吸附方程
温度/℃	K_L	q_max	R²	K_F	1/n	R²
10	4.309	0.088	0.990	0.076	0.582	0.979
25	7.276	0.070	0.980	0.076	0.553	0.994
35	10.263	0.085	0.992	0.088	0.500	0.978
45	30.325	0.105	0.994	0.149	0.453	0.969

Table 5 Thermodynamic parameters for uranium adsorption on sandstone

T/℃	K_L	ΔG⁰/ (kJ·mol^-1)	ΔH⁰/ (kJ·mol^-1)	ΔS⁰/ (J·mol^-1·K^-1)
10	4.31	-3.44	7.10	37.23
25	7.28	-4.92		40.32
35	10.26	-5.96		42.40
45	30.33	-9.02		50.69

Fig.2 Effects of pH on uranium adsorption on the sandstone

Fig.3 Effects of HCO 3 - concentration on the uranium adsorption capacity of sandstone and pH

Fig.4 Breakthrough curves of uranium adsorption in sandstone columns under different conditions a—CU=2 mg/L, Q=0.1 mL/min, C H C O 3 -=0; b—pH=7, Q=0.1 mL/min, C H C O 3 -=0 mmol/L; c—pH=7, CU=2 mg/L, C H C O 3 -=0; and d—pH=7, CU=2 mg/L, Q=0.1 mL/min。

Table 6 The fitted parameters of breakthrough curves of uranium adsorption in sandstone column

条件	k'_d/(mL·g^-1)	ω/(10³ min^-1)	R²
pH=4	9.82	1.720	0.995
pH=7	117	0.182	0.997
C_U=1 mg/L	159	0.122	0.936
C_U=2 mg/L	117	0.182	0.997
C_U=5 mg/L	23.9	0.828	0.989
流速0.1 mL/min	117	0.182	0.974
流速0.3 mL/min	49.5	0.604	0.977
流速0.5 mL/min	39.5	1.228	0.997
$C H C O 3 -$ =0	117	0.182	0.997
$C H C O 3 -$ =0.5 mmol/L	58.9	0.483	0.996
$C H C O 3 -$ =1.0 mmol/L	48.1	4.759	0.964

Table 6 The fitted parameters of breakthrough curves of uranium adsorption in sandstone column

条件	k'_d/(mL·g^-1)	ω/(10³ min^-1)	R²
pH=4	9.82	1.720	0.995
pH=7	117	0.182	0.997
C_U=1 mg/L	159	0.122	0.936
C_U=2 mg/L	117	0.182	0.997
C_U=5 mg/L	23.9	0.828	0.989
流速0.1 mL/min	117	0.182	0.974
流速0.3 mL/min	49.5	0.604	0.977
流速0.5 mL/min	39.5	1.228	0.997
$C H C O 3 -$ =0	117	0.182	0.997
$C H C O 3 -$ =0.5 mmol/L	58.9	0.483	0.996
$C H C O 3 -$ =1.0 mmol/L	48.1	4.759	0.964

Table 7 Partition coefficients from column and batch experiments

条件	柱实验分配系数 k'_d/(mL·g^-1)	批实验分配系数 k_d/(mL·g^-1)
pH=4	9.81	65.1
pH=7	117	637
C_U=1 mg/L	159	189
C_U=2 mg/L	117	133
C_U=5 mg/L	23.9	55.5
$C H C O 3 -$ =0	117	133
$C H C O 3 -$ =0.5 mmol/L	58.9	83.1
$C H C O 3 -$ =1.0 mmol/L	48.1	69.0

Table 7 Partition coefficients from column and batch experiments

条件	柱实验分配系数 k'_d/(mL·g^-1)	批实验分配系数 k_d/(mL·g^-1)
pH=4	9.81	65.1
pH=7	117	637
C_U=1 mg/L	159	189
C_U=2 mg/L	117	133
C_U=5 mg/L	23.9	55.5
$C H C O 3 -$ =0	117	133
$C H C O 3 -$ =0.5 mmol/L	58.9	83.1
$C H C O 3 -$ =1.0 mmol/L	48.1	69.0

References 41

[1]	张晓峰, 陈迪云, 彭燕, 等. 丁二酸改性茶油树木屑吸附铀的研究[J]. 环境科学, 2015, 36(5): 1686-1693.
[2]	黎广荣, 周义朋, 赵凯, 等. 砂岩型铀矿浸出矿物工艺学研究进展[J]. 有色金属(冶炼部分), 2021(8): 9-19.
[3]	左维, 谭凯旋. 新疆某地浸采铀矿山退役井场地下水污染特征[J]. 南华大学学报(自然科学版), 2014, 28(4): 28-34.
[4]	FU H Y, DING D X, SUI Y, et al. Transport of uranium(VI) in red soil in South China: influence of initial pH and carbonate concentration[J]. Environmental Science and Pollution Research, 2019, 26(36): 37125-37136. DOI URL
[5]	BRUGGEMAN C, MAES N. Uptake of uranium(VI) by pyrite under boom clay conditions: influence of dissolved organic carbon[J]. Environmental Science and Technology, 2010, 44(11): 4210-4216. DOI URL
[6]	廉欢, 高柏, 郭亚丹, 等. 某尾矿库区水环境中放射性核素铀的变化特征及影响因素[J]. 有色金属(冶炼部分), 2017(5): 64-68.
[7]	ZHANG Z B, LIU J, CAO X H, et al. Comparison of U(VI) adsorption onto nanoscale zero-valent iron and red soil in the presence of U(VI)-CO₃/Ca-U(VI)-CO₃ complexes[J]. Journal of Hazardous Materials, 2015, 300: 633-642. DOI URL
[8]	GE M T, WANG D J, YANG J W, et al. Co-transport of U(VI) and akaganéite colloids in water-saturated porous media: role of U(VI) concentration, pH and ionic strength[J]. Water Research, 2018, 147: 350-361. DOI URL
[9]	惠淑君. 铀在砂岩含水层介质中的吸附和转化特征[D]. 北京: 中国地质大学(北京), 2020.
[10]	惠淑君, 杨冰, 郭华明, 等. 不同因素对砂岩含水层介质吸附铀的影响[J]. 地学前缘, 2021, 28(5): 68-78.
[11]	丛伟, 张兴昌, 封晔. 不同CDE模型对硒在黄绵土中运移特性的模拟研究[J]. 水土保持学报, 2011, 25(3): 220-224.
[12]	MA J, MA Y L, WEI R F, et al. Phosphorus transport in different soil types and the contribution of control factors to phosphorus retardation[J]. Chemosphere, 2021, 276: 130012. DOI URL
[13]	Šimůnek J, Šejna M, Saito H, et al. The HYDRUS-1D software package for simulating the one-dimensional movement of water, heat, and multiple solutes in variably-saturated media[R]. California: University of California Riverside, 2013.
[14]	VAN GENUCHTEN M T, IMUNEK J Å, LEIJ F J, et al. STANMOD: model use, calibration, and validation[J]. Transactions of the ASABE. 2012, 55(4): 1355-1368. DOI URL
[15]	LI S C, WANG X L, HUANG Z Y, et al. Sorption and desorption of uranium(VI) on GMZ bentonite: effect of pH, ionic strength, foreign ions and humic substances[J]. Journal of Radioanalytical and Nuclear Chemistry, 2016, 308(3): 877-886. DOI URL
[16]	李松南. 以蛋壳为原料制备多种吸附材料及其铀吸附性能研究[D]. 哈尔滨: 哈尔滨工程大学, 2013.
[17]	赵凯. 改性天然菱铁矿除砷性能与应用[D]. 北京: 中国地质大学(北京), 2014.
[18]	赵凯, 郭华明, 李媛, 等. 天然菱铁矿改性及强化除砷研究[J]. 环境科学, 2012, 33(2): 459-468.
[19]	GUO H M, LI Y, ZHAO K. Arsenate removal from aqueous solution using synthetic siderite[J]. Journal of Hazardous Materials, 2010, 176(1/2/3): 174-180. DOI URL
[20]	SHAN Y, GUO H M. Fluoride adsorption on modified natural siderite: optimization and performance[J]. Chemical Engineering Journal, 2013, 223: 183-191. DOI URL
[21]	扶海鹰. 红壤中铀的迁移转化规律及控制方法研究[D]. 衡阳: 南华大学, 2019.
[22]	葛孟团. 胡敏酸和针铁矿胶体对U(Ⅵ)在饱和花岗岩颗粒柱中运移的影响研究[D]. 兰州: 兰州大学, 2019.
[23]	BACHMAF S, PLANER-FRIEDRICH B, MERKEL B J. Effect of sulfate, carbonate, and phosphate on the uranium(VI) sorption behavior onto bentonite[J]. Radiochimica Acta, 2008, 96(6): 359-366. DOI URL
[24]	YANG Z W, KANG M L, MA B, et al. Inhibition of U(VI) reduction by synthetic and natural pyrite[J]. Environmental Science and Technology, 2014, 48(18): 10716-10724. DOI URL
[25]	杜作勇, 王彦惠, 李东瑞, 等. 膨润土对U(Ⅵ)的吸附机理研究[J]. 核技术, 2019, 42(2): 22-29.
[26]	CUMBERLAND S A, WILSON S A, ETSCHMANN B, et al. Rapid immobilisation of U(VI) by eucalyptus bark: adsorption without reduction[J]. Applied Geochemistry, 2018, 96: 1-10. DOI URL
[27]	葛孟团. 水合氧化铁胶体对U(Ⅵ)在饱和石英砂柱中运移的影响[D]. 兰州: 兰州大学, 2016.
[28]	白静, 赵勇胜, 秦传玉. 重金属在含水层迁移实验方案设计[J]. 实验室研究与探索, 2018, 37(4): 45-48.
[29]	DANGELMAYR M A, REIMUS P W, WASSERMAN N L, et al. Laboratory column experiments and transport modeling to evaluate retardation of uranium in an aquifer downgradient of a uranium in situ recovery site[J]. Applied Geochemistry, 2017, 80: 1-13. DOI URL
[30]	张建明, 彭胜, 陈家军. 2,4-二氯苯酚在土壤中的吸附及其批实验与柱实验的分配系数比较[J]. 环境工程学报, 2012, 6(11): 4251-4256.
[31]	MARAQA M. Effects of fundamental differences between batch and miscible displacement techniques on sorption distribution coefficient[J]. Environmental Geology, 2001, 41(1/2): 219-228. DOI URL
[32]	BARNETT M O, JARDINE P M, BROOKS S C, et al. Adsorption and transport of uranium(VI) in subsurface media[J]. Soil Science Society of America Journal, 2000, 64(3): 908-917. DOI URL
[33]	Zheng C M, Bennett G D. Applied Contaminant Transport Modeling[J]. EOS Transactions American Geophysical Union, 2002, 77(48): 908-923.
[34]	何宝南. 纳米乳化油制备及其在多孔介质中的迁移释放模拟实验[D]. 北京: 中国地质大学(北京), 2017.
[35]	SCHWEICH D, SARDIN M, GAUDET J P. Measurement of a cation exchange isotherm from elution curves obtained in a soil column: preliminary results[J]. Soil Science Society of America Journal, 1983, 47(1): 32-37. DOI URL
[36]	张金利, 李宇. 碳纳米管-羟磷灰石对铅的吸附特性研究[J]. 环境科学, 2015, 36(7): 2554-2563.
[37]	NOURI L, GHODBANE I, HAMDAOUI O, et al. Batch sorption dynamics and equilibrium for the removal of cadmium ions from aqueous phase using wheat bran[J]. Journal of Hazardous Materials. 2007, 149(1): 115-125. DOI URL
[38]	GUELFO J L, WUNSCH A, MCCRAY J, et al. Subsurface transport potential of perfluoroalkyl acids (PFAAs): column experiments and modeling(Article)[J]. Journal of Contaminant Hydrology. 2020, 233: 103661.
[39]	AVASARALA S, LICHTNER P C, ALI A M S, et al. Reactive transport of U and V from abandoned uranium mine wastes[J]. Environmental Science and Technology, 2017, 51(21): 12385-12393. DOI URL
[40]	孙占学, 马文洁, 刘亚洁, 等. 地浸采铀矿山地下水环境修复研究进展[J]. 地学前缘, 2021, 28(5): 215-225.
[41]	昝金晶, 董一慧, 张卫民, 等. 铀在地下水系统中的赋存与迁移[J]. 有色金属(矿山部分), 2019, 71(6): 69-73, 77.