Quality and quantity characteristics of saline ice meltwater under different pretreatments
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摘要: 咸水结冰灌溉对重度盐碱地改良, 缓解淡水资源短缺具有重要现实意义。咸水冰融化过程中水盐分离的实质是盐分的再分配过程。为厘清前处理对咸水冰融化过程中水质及水量的影响, 本研究设计了曝气冰(A)、堆积冰(S)、破碎冰(C)和常规冰(R) 4种前处理, 及4个初始矿化度(0 g∙L−1、5 g∙L−1、10 g∙L−1、15 g∙L−1), 对比分析融水过程中水量和水质的动态变化。结果表明, 曝气、堆积和破碎处理相对常规冰都能显著减少融化时间, 各处理融化时间为破碎冰<堆积冰<曝气冰<常规冰; 单位时间融出水量均呈先快速升高, 后缓慢降低的趋势, 峰值水量为常规冰<曝气冰<堆积冰<破碎冰。随着融化过程的进行, 融水矿化度快速下降, 之后逐渐平缓; 其中, 破碎冰初始和结束时融水矿化度和钠吸附比(SAR)均显著低于常规冰; 且初始矿化度为5 g∙L−1时破碎冰的淡水(<1 g∙L−1)融出量高达33.26%, 显著高于同矿化度的其他前处理冰体。可见, 前处理措施可以显著改变咸水冰融化过程中的水盐再分配过程, 这为地下咸水资源利用时通过咸水冰前处理提高盐分淋洗能力提供了理论依据。Abstract: Saline ice irrigation has a positive effect on heavy saline land reclamation and is of great practical importance for alleviating freshwater shortages. Water-salt separation is a salt redistribution process during saline ice melting. We aimed to clarify the influence of pretreatment on the quantity and quality of melted water and the melting duration of saline ice. To achieve these parameters, four ice pretreatments, including aerated ice, stacked ice, crushed ice, and regular ice; and four initial total dissolved solids (TDS) of saline ice of 0, 5, 10, and 15 g·L−1 were used to compare and analyze the dynamics of water quantity and quality during the saline ice melting process. The results showed that aeration, stacking, and crushing treatments significantly reduced the melting duration compared with that of regular ice. The melting duration of each treatment was crushed ice < stacked ice < aerated ice < regular ice. The meltwater volume per unit time showed a trend of rapid increase followed by a gradual decrease, with the peak water volume in the order of regular ice < aerated ice < stacked ice < crushed ice. As the melting process continued, the TDS of the meltwater decreased rapidly and finally stabilized. Among all the pretreatments, the TDS and sodium adsorption ratio (SAR) of meltwater from crushed ice were significantly lower than those from regular ice. The highest freshwater (<1 g∙L−1) yield was 33.26% at the initial TDS of 5 g∙L−1 for crushed ice. Pretreatment measures can significantly change the water-salt reallocation process of saline ice melting, which provides a theoretical basis for utilization of saline groundwater resources.
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Key words:
- Saline ice /
- Melting process /
- Total dissolved solids /
- Sodium adsorption ratio
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图 1 试验装置照片
图中从左到右分别为常规冰、曝气冰、堆积冰、破碎冰。From left to right are regular ice, aerated ice, stacked ice and crushed ice, respectively.
Figure 1. Photograph of the experimental setup
图 2 不同前处理下不同矿化度咸水冰的融化历时
图中R、A、S、C分别代表常规冰、曝气冰、堆积冰和破碎冰。R, A, S and C represent regular ice, aerated ice, stacked ice and crushed ice respectively.
Figure 2. Comparison of melting times of saline ice with different salinities under different pretreatments
图 3 不同初始矿化度下各前处理咸水冰融水水量动态
图中R、A、S、C分别代表常规冰、曝气冰、堆积冰和破碎冰。R, A, S and C represent regular ice, aerated ice, stacked ice and crushed ice, respectively.
Figure 3. Dynamics of the meltwater volumes of saline ice with different salinities under different pretreatments
图 4 不同前处理和矿化度条件下咸水冰融水盐分动态
图中R、A、S、C分别代表常规冰、曝气冰、堆积冰和破碎冰。R, A, S and C represent regular ice, aerated ice, stacked ice and crushed ice, respectively.
Figure 4. Salinity dynamics of meltwater of saline ice with different salinities under different pretreatments
图 5 不同前处理和矿化度条件下咸水冰融水钠吸附比动态
图中R、A、S、C分别代表常规冰、曝气冰、堆积冰和破碎冰。R, A, S and C represent regular ice, aerated ice, stacked ice and crushed ice, respectively.
Figure 5. Dynamics of sodium adsorption ratio of meltwater of saline ice with different salinities under different pretreatments
图 6 不同前处理不同矿化度咸水的各矿化度融水占比
字母代表前处理方法, R、A、S、C分别指常规冰、曝气冰、堆积冰、破碎冰; 其后数字代表初始矿化度, 如“R5”表示初始矿化度为5 g·L−1的常规冰。The letters in the treatments indicate the pretreatment methods, where R, A, S, and C refer to regular ice, aerated ice, stacked ice, and crushed ice, respectively; the numbers following letters indicate the initial salinity of saline ice, such as R5 means the regular ice pretreatment with an initial salinity of 5 g·L−1.
Figure 6. Salt redistribution of meltwater of saline ice with different salnities under different pretreatments
表 1 试验用不同矿化度咸水的离子组成
Table 1. Ion composition of the saline water of different salinities
% 离子 Ion 5 g∙L−1 10 g∙L−1 15 g∙L−1 K+ 0.029 0.055 0.089 Na+ 1.938 3.952 5.970 Ca2+ 0.030 0.059 0.056 Mg2+ 0.019 0.038 0.048 SO42− 0.146 0.258 0.314 Cl− 3.662 7.649 12.022 HCO3− 0.030 0.039 0.030 
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表 2 不同处理下咸水冰融水矿化度(TDS)和钠吸附比(SAR)始末变化
Table 2. Comparison of total dissolved solids (TDS) and sodium adsorption ratio (SAR) in meltwater between the starting and ending melting of saline ice with different salinities under different pretreatments
矿化度
Salinity (g∙L−1)前处理
Pre-treatment开始 Start 结束 End TDS SAR TDS SAR 数值 Value (g∙L−1) Std. E 数值 Value Std. E 数值 Value (g∙L−1) Std. E 数值 Value Std. E 5 常规冰 Regular ice 288.61a 23.79 10.65a 1.34 0.20ab 0.17 0.38bc 0.08 曝气冰 Aerated ice 63.58cde 7.06 6.16cde 0.51 0.26ab 0.12 0.51abc 0.11 堆积冰 Stacked ice 71.16cde 24.32 7.34abcd 1.45 0.68a 0.15 0.84a 0.03 破碎冰 Crushed ice 14.54e 5.27 3.40e 1.00 0.06b 0.05 0.16c 0.09 10 常规冰 Regular ice 270.69a 37.65 10.54a 1.94 0.26ab 0.07 0.40abc 0.26 曝气冰 Aerated ice 178.95bc 18.64 10.28ab 1.62 0.02ab 0.04 0.04bc 0.00 堆积冰 Stacked ice 123.49cd 29.17 7.07bcd 2.03 0.77a 0.28 0.69ab 0.40 破碎冰 Crushed ice 31.09de 3.72 4.06de 0.36 0.07b 0.06 0.24bc 0.15 15 常规冰 Regular ice 291.30a 126.57 8.25abc 1.75 0.50ab 0.49 0.33abc 0.29 曝气冰 Aerated ice 287.23a 77.82 7.96abc 2.87 0.42ab 0.25 0.50abc 0.21 堆积冰 Stacked ice 246.10ab 39.57 8.08abc 3.03 0.97a 0.73 0.66abc 0.50 破碎冰 Crushed ice 110.52cd 20.94 6.31cde 1.25 0.11ab 0.03 0.23bc 0.14 Std. E为参数标准误差; 不同小写字母表示不同处理间差异达显著水平(P<0.05)。Std. E is the standard error. Different lowercase letters mean significant differences among different treatments at P<0.05 level.
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表 3 不同前处理下不同矿化度咸水冰融水矿化度幂函数(
$ y=a \cdot {x}^{b} $ )拟合参数表Table 3. Parameters of the fitted power function (y=a·xb) of total dissolved solids in meltwater (y) of saline ice with different salinities (x) under different pretreatments
矿化度
Salinity (g∙L−1)前处理
Pretreatmenta b R2 n 值 Value Std. E Sig. 值 Value Std. E Sig. 5 常规冰 Regular ice 100.90 4.12 <0.01 −1.55 0.06 <0.01 0.98 28 曝气冰 Aerated ice 179.58 9.20 <0.01 −2.53 0.09 <0.01 0.99 23 堆积冰 Stacked ice 70.75 1.11 <0.01 −2.94 0.09 <0.01 0.99 18 破碎冰 Crushed ice 101.04 8.15 <0.01 −2.77 0.10 <0.01 0.99 15 10 常规冰 Regular ice 142.42 9.81 <0.01 −1.10 0.09 <0.01 0.88 28 曝气冰 Aerated ice 184.10 3.69 <0.01 −1.71 0.05 <0.01 0.99 27 堆积冰 Stacked ice 128.56 4.64 <0.01 −1.86 0.10 <0.01 0.98 20 破碎冰 Crushed ice 550.99 109.50 <0.01 −3.08 0.19 <0.01 0.98 16 15 常规冰 Regular ice 167.32 12.14 <0.01 −1.02 0.09 <0.01 0.86 29 曝气冰 Aerated ice 308.80 13.74 <0.01 −1.60 0.09 <0.01 0.95 27 堆积冰 Stacked ice 251.75 6.93 <0.01 −2.08 0.09 <0.01 0.99 20 破碎冰 Crushed ice 9321.27 1836.00 <0.01 −4.86 0.20 <0.01 0.99 17 表中a、b为幂函数中的拟合参数; R2为拟合精度; Std. E为参数标准误差; Sig. 为拟合显著度; n为样本数。a, b are the fitting constants in the power function; R2 is the fitting accuracy; Std. E is the standard error; Sig. is the significance of the fitness; n is the number of data used for fitting.
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表 4 不同前处理下不同矿化度咸水冰融水钠吸附比幂函数(
$y=a \cdot {x}^{b}$ )的拟合参数Table 4. Parameters of the fitted power function (y=a·xb) of sodium adsorption ratio of meltwater (y) of saline ice with different salinities (x) under different pretreatments
矿化度
Salinity (g∙L−1)前处理
Pretreatmenta b R2 n 值 Value Std. E Sig. 值 Value Std. E Sig. 5 常规冰 Regular ice 6.89 0.27 <0.01 −0.79 0.04 <0.01 0.93 28 曝气冰 Aerated ice 9.84 0.88 <0.01 −1.06 0.05 <0.01 0.94 23 堆积冰 Stacked ice 6.85 0.26 <0.01 −1.10 0.05 <0.01 0.97 18 破碎冰 Crushed ice 17.18 3.53 <0.01 −1.95 0.14 <0.01 0.96 15 10 常规冰 Regular ice 8.05 0.51 <0.01 −0.73 0.06 <0.01 0.83 28 曝气冰 Aerated ice 14.48 1.13 <0.01 −1.33 0.04 <0.01 0.93 26 堆积冰 Stacked ice 7.51 0.26 <0.01 −0.93 0.04 <0.01 0.97 20 破碎冰 Crushed ice 26.06 4.75 <0.01 −1.95 0.14 <0.01 0.96 16 15 常规冰 Regular ice 7.32 0.61 <0.01 −0.63 0.07 <0.01 0.72 29 曝气冰 Aerated ice 15.27 1.94 <0.01 −1.25 0.07 <0.01 0.85 27 堆积冰 Stacked ice 8.94 0.48 <0.01 −1.00 0.06 <0.01 0.93 20 破碎冰 Crushed ice 51.34 13.32 <0.01 −2.12 0.18 <0.01 0.97 17 表中a、b为幂函数中的拟合参数; R2为拟合精度; Std. E为参数标准误差; Sig.为拟合显著度; n为样本数。a, b are the fitting constants in the power function; R2 is the fitting accuracy; Std. E is the standard error; Sig. is the significance of the fitness; n is the number of data used for fitting.
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表 5 不同前处理下不同矿化度咸水冰单位体积融水矿化度及融出该水量时的咸水冰脱盐率
Table 5. Total dissolved solids (TDS) per unit volume of meltwater and desalination ratio at specific melting stage of saline ice with different salinities under different pretreatments
矿化度
TDS (g∙L−1)前处理
Pretreatment融水矿化度
TDS of melted water (g∙L−1)咸水冰融化各阶段脱盐率
Desalination ratio at each melting stage (%)0%~25% 25%~50% 50%~75% 75%~100% 25% 50% 75% 5 常规冰 Regular ice 14.38±0.78f 2.65±0.31e 2.16±0.26bc 0.80±0.23cd 71.92±3.91cde 85.16±2.44cd 95.99±1.30bc 曝气冰 Aerated ice 14.38±0.60f 2.97±0.58e 2.04±0.24bc 0.61±0.16cd 71.88±3.00cde 86.74±1.32cd 96.93±1.18b 堆积冰 Stacked ice 13.51±0.66f 3.27±0.43e 1.96±0.25bc 1.26±0.04c 67.57±3.30de 83.94±1.14d 93.72±1.26d 破碎冰 Crushed ice 12.84±0.77f 5.02±0.51d 1.78±0.26c 0.36±0.07d 64.21±3.83e 89.30±1.63bc 98.20±1.31a 10 常规冰 Regular ice 31.72±0.79d 5.71±0.55d 2.07±0.25bc 0.50±0.16d 79.30±1.97abc 93.57±0.98ab 98.75±0.64a 曝气冰 Aerated ice 31.63±0.22d 5.39±0.09d 2.46±0.29bc 0.52±0.05d 79.08±0.54abc 92.54±0.61ab 98.69±0.72a 堆积冰 Stacked ice 27.92±0.35e 5.92±0.22d 3.98±0.34b 2.17±0.52b 69.81±0.87de 84.61±0.44d 94.57±0.86cd 破碎冰 Crushed ice 25.52±1.85e 11.58±1.33b 2.42±0.45bc 0.47±0.11d 63.81±4.63e 92.76±1.39ab 98.81±1.12a 15 常规冰 Regular ice 50.62±2.58a 6.45±1.87cd 2.16±0.90bc 0.76±0.16cd 84.37±4.30a 95.12±1.57a 98.73±1.50a 曝气冰 Aerated ice 48.40±2.36a 8.26±1.92c 2.56±0.49bc 0.78±0.17cd 80.67±3.94ab 94.44±1.10a 98.70±0.82a 堆积冰 Stacked ice 43.93±3.34b 7.98±1.04c 5.44±1.87a 2.66±0.47a 73.21±5.57bcd 86.50±3.87cd 95.57±3.12bcd 破碎冰 Crushed ice 40.29±1.07c 15.24±0.82a 3.58±1.24bc 0.89±0.47cd 67.16±1.79de 92.56±2.69ab 98.52±2.06a 不同小写字母表示不同处理间差异达显著水平(P<0.05)。Different lowercase letters mean significant differences among different treatments at P<0.05 level.
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