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天然有机物与钙镁离子对水环境中氧化石墨烯稳定性的复合影响
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作者 方华 王燕 +3 位作者 李璇 章婷婷 赵怡 徐林 《生态环境学报》 北大核心 2025年第5期754-762,共9页
氧化石墨烯(Graphene oxide,GO)是应用最广泛的碳纳米材料,可造成潜在的水生态环境风险。进入水体后,GO将受各类环境因子的影响诱发凝聚和沉降而改变其稳定性和生态毒性。其中,最重要的影响因素为天然有机物(natural organic matters,NO... 氧化石墨烯(Graphene oxide,GO)是应用最广泛的碳纳米材料,可造成潜在的水生态环境风险。进入水体后,GO将受各类环境因子的影响诱发凝聚和沉降而改变其稳定性和生态毒性。其中,最重要的影响因素为天然有机物(natural organic matters,NOMs)和电解质。目前NOMs特性及其与金属离子间复合作用对水中GO稳定性的影响机制尚不清晰。通过对水中GO凝聚、沉降和再分散过程的动力学分析,研究了典型NOMs和电解质对水中GO稳定性的复合影响。结果表明,电解质可压缩GO表面双电层引发其在水中凝聚。凝聚后GO可进一步沉降并从水中分离,沉降速度与凝聚速度呈正相关。相较于Mg^(2+),Ca^(2+)与GO的亲和力更强,可使GO更快地凝聚和沉降。NOMs不会直接诱发GO凝聚,但可通过空间位阻作用抑制凝聚。相较于海藻酸钠,腐殖酸(humic acid,HA)更易被GO吸附,抑制凝聚作用更强。HA可与Ca^(2+)发生络合凝聚;GO、Ca^(2+)和HA共存时,引发了多种凝聚过程的协同,使凝聚速度加快。有机物分子量越大,对GO凝聚和沉降的抑制作用越强。再分散过程使GO凝聚体分解,再分散后的GO可再次自发凝聚和沉降,但速度变慢。有机物存在进一步增强了再分散后GO在水中的稳定性。该研究可为全面评估GO在水中的稳定性和生态风险提供理论依据。 展开更多
关键词 氧化石墨烯 天然有机物 钙镁离子 凝聚动力学 沉降动力学 再分散
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水体离子强度、pH值和腐殖酸浓度对石墨相氮化碳沉降的影响 被引量:2
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作者 董姝楠 夏继红 +2 位作者 王为木 刘慧 盛丽婷 《农业工程学报》 EI CAS CSCD 北大核心 2021年第17期218-224,共7页
为解决农业环境中石墨相氮化碳(g-C_(3)N_(4))的风险评估、污染预测等问题,该研究以g-C_(3)N_(4)为研究对象,通过室内沉降试验、沉降模型计算、DLVO(Derjaguine Landaue Verweye Overbeek)理论计算相结合的研究方法,考察离子强度(Ionic ... 为解决农业环境中石墨相氮化碳(g-C_(3)N_(4))的风险评估、污染预测等问题,该研究以g-C_(3)N_(4)为研究对象,通过室内沉降试验、沉降模型计算、DLVO(Derjaguine Landaue Verweye Overbeek)理论计算相结合的研究方法,考察离子强度(Ionic Strength,IS)、pH值和腐殖酸(Humic Acid,HA)3种典型水环境因素对g-C_(3)N_(4)沉降与分散稳定性的影响。研究结果表明,g-C_(3)N_(4)的沉降随水环境IS升高而明显增强,IS由0上升至50.0 mmol/L,360 min后g-C_(3)N_(4)悬液的终点标准化浓度(C/C0)由0.86变为0.58。水环境pH值变化对g-C_(3)N_(4)沉降与分散稳定性影响较小,pH值由2上升至4,360 min后g-C_(3)N_(4)悬液的终点C/C0由0.63变为0.57;而pH值由4上升至10,360 min后g-C_(3)N_(4)悬液的终点C/C0由0.57变为0.78。水环境中HA的存在能够增强g-C_(3)N_(4)的分散稳定性,HA浓度由0提升至10.0 mg/L,360 min后g-C_(3)N_(4)悬液的终点C/C0由0.60变为0.91。一阶动力学沉降模型能够有效模拟水体中g-C_(3)N_(4)的沉降动力学曲线,DLVO理论的计算结果能够反映出不同条件下g-C_(3)N_(4)颗粒间的势能分布。研究结果对于准确分析评估农业环境中g-C_(3)N_(4)的环境风险和生态安全具有重要意义。 展开更多
关键词 污染 试验 水环境 光催化 石墨相氮化碳 沉降动力学 分散稳定性
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浸出矿浆固液分离过程中颗粒的沉降行为研究 被引量:2
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作者 朱坤娥 秦树辰 +1 位作者 郑朝振 刘三平 《有色金属(冶炼部分)》 CAS 北大核心 2019年第11期7-11,共5页
对沉降过程中颗粒物受力、胶体荷电机理和颗粒物沉降动力学特性进行了详细分析,并对铜钴浸出矿浆和高硅锌焙砂中性浸出矿浆两种浸出矿浆性质进行了测定及对比研究,分析了矿浆中黏度的变化规律和矿物颗粒性质对沉降行为的影响。
关键词 浸出矿浆 沉降动力学 颗粒 沉降行为
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Numerical study of flocculation settling and thickening of whole-tailings in deep cone thickener using CFD approach 被引量:12
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作者 WU Ai-xiang RUAN Zhu-en +3 位作者 LI Cui-ping WANG Shao-yong WANG Yong WANG Jian-dong 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第3期711-718,共8页
Deep cone thickener (DCT) is the key equipment in cemented paste backfill (CPB), so it is essential to study the flocculation settling and thickening characteristics of the whole-tailings in DCT. Coupled with populati... Deep cone thickener (DCT) is the key equipment in cemented paste backfill (CPB), so it is essential to study the flocculation settling and thickening characteristics of the whole-tailings in DCT. Coupled with population balance model (PBM), computational fluid dynamics (CFD) was used to study the characteristics, namely particle size distribution (PSD) and underflow concentration in DCT. Based on actual production, the effects of rake rotational speed, feed rate and tailings slurry concentration were simulated and analyzed in a certain range. The PSD varied with rake rational speed, feed rate and tailings slurry concentration almost in the same trend, but the influence of feed rate was less than that of rake rational speed and tailings slurry concentration. The underflow concentration increased at first and then declined with rake rational speed and feed rate, but it rose and fell with the tailings slurry concentration. Finally, the optimal key parameters on the flocculation settling and thickening of the whole-tailings in DCT were obtained: rake rotational speed of 17 r/min, feed rate of 3.25 m^3/h and tailings slurry concentration of 20%, giving the reference values to the industrial production in Baishitamu Copper Mine. 展开更多
关键词 deep cone thickener flocculation settling THICKENING whole-tailings computational fluid dynamics
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Ground movement mechanism in tectonic stress metal mines with steep structure planes 被引量:4
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作者 夏开宗 陈从新 +2 位作者 刘秀敏 郑元 付华 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第9期2092-2104,共13页
When mining metal mines with steep structure planes by the caving method,there is a mechanical model in which the horizontal stress on the rock mass is simplified as a column before surface subsidence.The model is use... When mining metal mines with steep structure planes by the caving method,there is a mechanical model in which the horizontal stress on the rock mass is simplified as a column before surface subsidence.The model is used to deduce critical support load and limiting column length for a given horizontal stress and support pressure.Considering the impact of the column effect,a method is proposed to determine the movement of the ground and caving area in a mine.After surface subsidence,the horizontal stress on a surrounding rock mass can be simplified to a cantilever beam mechanical model.Expressions for its bending fracture length are deduced,and a method is given to determine its stability.On this basis,an explanation for the large ground movement and subsidence scope was given.A case study shows that the damage effect of column and cantilever beam is significant for ground movement in metal-ore mine,and an appropriate correction value should be applied when designing for its angle of ground movements. 展开更多
关键词 mining engineering underground mining ground movement horizontal stress COLUMN cantilever pillar
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