The sequestration of Al³⁺ by etidronic acid (1‑Hydroxyethane‑1,1‑diyil)bis(phosphonic acid) (HEDPA), nitrilotriacetic acid and its phosphonic derivatives, namely N‑(phosphonomethyl)iminodiacetic acid (PMIDA, NTAP), N,N‑bis‑(phosphonomethyl)glycine (NTA2P) and [bis(phosphonomethyl)amino]methylphosphonic acid (NTA3P) was studied in aqueous solution at T = 298.15 K and I = 0.15 mol L⁻¹ in NaCl. Formation constants and speciation models are discussed on the basis of potentiometric results. The speciation models found for all the systems include MLH, ML and MLOH species, in addition for Al³⁺-NTA system ML(OH)₂ and M₂L₂(OH)₂, for NTAP system ML₂, for NTA2P and NTA3P systems MLH₂ species, for HEDPA system ML₂ and ML₂OH species were detected as well. The formation constant values for ML species show the trend NTA < NTAP < HEDP < NTA2P < NTA3P. Investigations using ¹H NMR spectroscopy were also performed for the study of Al³⁺-NTAP system. The ¹H NMR findings are in agreement with the speciation model obtained by potentiometry, confirming the stabilities of the main species. The dependence of formation constants on ionic strength over the range I = 0.15 to 1 mol L⁻¹ in NaCl is also reported for NTA, NTAP, NTA2P systems. Enthalpy change values obtained by titration calorimetry at T = 298.15 K and I = 0.15 mol L⁻¹ in NaCl, for the main Al³⁺-NTA, -NTAP, -NTA2P and NTA3P species, are mainly endothermic, as typical for hard-hard interactions. The sequestering ability of the ligands under study towards Al³⁺ was also evaluated, under different pH conditions by the empirical parameter pL_0.5.

乙二胺四乙酸（1-乙氧基乙烷-1,1-二乙腈）双（膦酸）（HEDPA），次氮基三乙酸及其膦酸酯衍生物，即N-（膦酰基甲基）亚氨基二乙酸（PMIDA，NTAP），对Al ³⁺的螯合，在水溶液中，在T  = 298.15 K和I  = 0.15 mol L ^-1的条件下研究了N，N-双-（膦酰基甲基）甘氨酸（NTA2P）和[双（膦酰基甲基）氨基]甲基膦酸（NTA3P）。在氯化钠中。在电位测量结果的基础上讨论了形成常数和形态模型。找到的所有系统的形态模型包括MLH，ML和MLOH物种中，除了用于铝³⁺ - NTA系统ML（OH）₂和M ₂大号₂（OH）₂，用于NTAP系统ML ₂，用于NTA2P和NTA3P系统MLH ₂种类，对于HEDPA系统也检测到ML ₂和ML ₂ OH种类。ML物种的形成常数值显示趋势NTA  <  NTAP <  HEDP  <  NTA2P  <  NTA3P。使用调查^1个也为Al的研究中进行的1 H NMR光谱³⁺ - NTAP系统。的^1个1 H NMR发现与通过电位获得，证实主要种类的稳定性的形态模型的协议。对于NTA，NTAP，NTA2P系统，还报道了在NaCl中，在I  = 0.15至1 mol L ^-1范围内，形成常数对离子强度的依赖性。通过滴定量热法在T  = 298.15 K和I下获得的焓变值 = 0.15摩尔大号^-1在NaCl，对于主铝³⁺ - NTA，-NTAP，-NTA2P和NTA3P物种，主要是吸热的，作为典型的硬-硬相互作用。还通过经验参数pL _0.5评估了在不同pH条件下所研究的配体对Al ³⁺的螯合能力。