水质参数对功能化石墨烯在水中凝聚行为的影响

采用动态光散射技术研究了不同价态阳离子、富里酸（FA）等对两种功能化石墨烯（FG）悬浮凝聚行为的影响机制.结果表明：FG分别在含不同浓度Na⁺、Ca²⁺和La³⁺的电解质溶液中，其临界聚集浓度（CCC）值范围为221~263，3~4，0.05~0.07mmol/L，符合经典的DLVO理论与Schulze-Hardy法则.5种FA亚组分均可显著抑制FG在水体中的凝聚，加入5mg/L的FA亚组分后，在不同浓度的Ca²⁺和La³⁺的电解质溶液中，FG-OH （FG-COOH）的CCC值分别增大12.5%~37.5%（3.2%~4.5%）和4.2%~25.7%（10%~46%）.FG的CCC值与FA亚组分的C、H含量和H/C比显著正相关（P<0.05），与O含量、O/C比和羧基C含量显著负相关（P<0.05）.差分荧光光谱研究表明随着FG的加入，FA的荧光强度逐渐降低，二者发生相互作用.

Influence of water quality parameters on the aggregation behaviors of functionalized graphene in aquatic system

The influence mechanisms of cations with different valences and fulvic acid (FA) on aggregation behaviours of two functionalized graphene (FG) were investigated by dynamic light scattering technique. The critical coagulation concentration (CCC) values of FG in electrolyte solutions containing Na⁺, Ca²⁺ and La³⁺ ranged from 221~263, 3~4 and 0.05~0.07mmol/L respectively, which were consistent with DLVO theory and Schulze-Hardy rule. The five FA sub-fractions can significantly inhibit the aggregation of FG in water. After adding 5mg/L FA sub-fractions, the CCC values of FG-OH (FG-COOH) increased 12.5%~37.5% (3.2%~4.5%) and 4.2%~25.7% (10%~46%), respectively in electrolyte solutions containing Ca²⁺ and La³⁺. The CCC values of FG were positively significantly correlated with the C content, H content and H/C ratio (P<0.05), and negatively significantly correlated with the O content, O/C ratio and carboxylic C of FA sub-fractions (P<0.05). The fluorescence intensity of FA gradually decreased with the addition of FG indicating the interactions between FG and FA.