• 关键词：暗棕壤  粗胡敏素  铜  吸附  影响因素  胡敏酸

• 基金项目：国家自然科学基金(No.40471076,40871107);吉林农业大学博士后基金

• 张晋京
• 吉林农业大学资源与环境学院, 长春 130118

• 王帅
• 吉林农业大学资源与环境学院, 长春 130118

• 窦森
• 吉林农业大学资源与环境学院, 长春 130118

• 王玉军
• 吉林农业大学资源与环境学院, 长春 130118

• 宋祥云
• 南京农业大学农业资源与生态环境研究所, 南京 210095

• 摘要：以暗棕壤为供试土壤,应用批量平衡法,研究了不同pH、离子强度、温度、Cu²⁺浓度和反应时间条件下,粗胡敏素(CHM)对Cu²⁺的吸附作用,并与相应胡敏酸(HA)的吸附作用进行了比较.结果表明:pH为2～4时,CHM对Cu²⁺的吸附率较低;随着pH的提高,吸附率增大;pH=7时,吸附率接近100%.随离子强度(0.01～1.00mol·L^-1)增加,CHM对Cu²⁺的吸附量下降,其对Cu²⁺的吸附包括电性和专性吸附2种作用.随温度(25～45℃)的升高和Cu²⁺浓度(0～1000mg·L^-1)的增加,CHM对Cu²⁺的吸附量增加,并与Langmuir方程拟合程度最好,25℃和45℃时的最大吸附量分别为12.61mg·g^-1和14.31mg·g^-1·CHM对Cu²⁺的吸附动力学过程可划分为快速(0～120min)和慢速(120～1440min)反应阶段,抛物线扩散方程拟合效果最好.与HA相比,CHM对Cu²⁺的吸附规律与HA相似,但其吸附量低于HA;表观热力学参数(ΔG、ΔH、ΔS)表明,CHM对Cu²⁺的吸附是自发、吸热和熵增加的过程,Cu²⁺在CHM上的吸附力大、活动性小、不易解吸,而在HA上的吸附力小、活动性大、容易解吸;活化能(E)和活化热力学参数(ΔG^#、ΔH^#、ΔS^#)表明,CHM对Cu²⁺吸附所需能量多、活化熵高、吸附速率小,而HA对Cu²⁺吸附所需能量少、活化熵低、吸附速率大.

• Abstract：Humin (HM) is the most insoluble fraction of the humic substances. It plays an important role in the mobility and bioavailability of heavy metals in the environment. In this paper, crude HM (CHM) is defined as HM strongly bonded to the soil mineral matter in order to distinguish organic-mineral HM from organic HM. Adsorption of Cu²⁺ on CHM, isolated from dark-brown soil, was studied as a function of pH, ionic strength, temperature, Cu²⁺ concentration and contact time by the batch equilibrium method. Differences of Cu²⁺ adsorption on CHM and HA were compared. Adsorption of Cu²⁺ on CHM increased with increasing initial pH from 2 to 7. The percent adsorbed was low at pH= 2～4 and reached nearly 100% at pH= 7. However, Cu²⁺ adsorption decreased with increasing ionic strength from 0.01 to 1.00 mol·L^-1. Cu²⁺ was retained on CHM by both non-specific and specific bonding. The adsorption capacity of Cu²⁺ on CHM increased with the increase of temperature from 25 to 45℃ and Cu²⁺ concentration from 0 to 1000 mg·L^-1, and the adsorption isotherms could be best fit by the Langmuir equation. The maximum Cu²⁺ adsorption capacity of CHM was 12.61 mg·g^-1 at 25℃ and 14.31 mg·g^-1 at 45℃. Adsorption kinetics of Cu²⁺ on CHM consisted of a rapid reaction from 0 to 120 min, followed by a slow one from 120 to 1440 min, and the kinetic processes could be best described by the parabolic diffusion equation. Characteristics of Cu²⁺ adsorption on CHM were basically identical to those on HA, while the adsorption capacity of the former was lower. The apparent thermodynamic parameters (ΔG, ΔH, ΔS) indicated that the adsorption of Cu²⁺ on CHM was spontaneous, endothermic and entropically unfavorable, and the desorption of Cu²⁺ from CHMwas more difficult than that from HA. Based on the energy of activation (E) and thermodynamic parameters of activation (ΔG^#、ΔH^#、ΔS^#), the adsorption rate of Cu²⁺on CHM was slower than that on HA.

• Key words：dark-brown soil  crude humin  copper  adsorption  affecting factors  humic acid

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