This pivotal study introduces a new methodology for the sustainable remediation of Cd2+ ions from industrial mining effluent. The cornerstone of this innovative approach is the deployment of a meticulously engineered α-acylamino thioamide composite (α-AATh), synthesized via a one-pot Ugi four-component strategy (Ugi-4CRs). This composite was found to exhibit high sequestration capabilities, achieving a remarkable Cd2+ ions retention capacity of 186 mg/g. Comprehensive characterization, employing advanced analytical techniques such as (BET) analysis conclusively revealed a specific pore volume (VP) of 0.31 cm3⋅g−1, a substantial surface area (SBET) of 237 m2⋅g−1, and an average pore diameter (DP) of 19 nm, unequivocally confirming the composite's mesoporous structure and favorable Type IV isotherm characteristics. Rigorous experimentation elucidated the optimal parameters for Cd2+ ions capture, demonstrating that at 25 °C, pH 3.5, with a 10-min agitation period and an initial concentration of 1000 mg/L, the α-AATh composite consistently achieves a robust maximum retention capacity of 186 mg/g. Kinetic modeling, specifically the pseudo-first-order kinetic model, accurately predicted the adsorption kinetics, yielding a retention capacity of 188.36 mg/g with an adsorption rate of 0.5944 min−1. Furthermore, equilibrium isotherm modeling conclusively demonstrated a superior fit with the Langmuir isotherm, surpassing the Freundlich isotherm, with theoretical Langmuir values reaching 188.67 mg/g. The Dubinin-Radushkevich (D-R) isotherm model provided chemisorption as the dominant process, evidenced by adsorption energy (ED) of 9.121 kJ/mol and a theoretical retention power of 187.524 mg/g. Additionally, the heat of sorption (bT) was determined to be 10.252 kJ/mol, closely aligning with the D-R isotherm's adsorption energy, thereby reinforcing the conclusion of a chemisorption-driven process. The provided thermodynamic analysis conclusively demonstrates that the adsorption process is notably exothermic, spontaneous, and thermodynamically favorable at reduced temperatures. Eluting Cd2+ ions from the saturated α-AATh, achieving an impressive 99% recovery rate through the application of 2 M H2SO4. Furthermore, the composite exhibits remarkable reproducibility, maintaining its robust performance over ten adsorption/elution/scrubbing cycles with negligible capacity loss, boasting an outstanding 99.5% efficiency. Crucially, the efficacy of α-AATh in extracting Cd2+ ions from Saudi Arabia's industrial mining discharge wastewater rigorously adheres to the stringent safety standards stipulated by both WHO and FAO guidelines, thereby guaranteeing the potability and safety of the treated water after a single treatment cycle.

Efficient Ugi-Based Synthesis of a Novel α-Acylamino Thioamide for the Elimination of Cadmium Ions from Wastewater

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发表日期：

2025年10月4日

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Mahmoud Mohery,
Gamal M. A. Mahran,
Enaam A. Al-Harthi,
Bahig M. Atia,
Mohamed A. Gado

摘要

This pivotal study introduces a new methodology for the sustainable remediation of Cd²⁺ ions from industrial mining effluent. The cornerstone of this innovative approach is the deployment of a meticulously engineered α-acylamino thioamide composite (α-AATh), synthesized via a one-pot Ugi four-component strategy (Ugi-4CRs). This composite was found to exhibit high sequestration capabilities, achieving a remarkable Cd²⁺ ions retention capacity of 186 mg/g. Comprehensive characterization, employing advanced analytical techniques such as (BET) analysis conclusively revealed a specific pore volume (V_P) of 0.31 cm³⋅g⁻¹, a substantial surface area (S_BET) of 237 m²⋅g⁻¹, and an average pore diameter (D_P) of 19 nm, unequivocally confirming the composite's mesoporous structure and favorable Type IV isotherm characteristics. Rigorous experimentation elucidated the optimal parameters for Cd²⁺ ions capture, demonstrating that at 25 °C, pH 3.5, with a 10-min agitation period and an initial concentration of 1000 mg/L, the α-AATh composite consistently achieves a robust maximum retention capacity of 186 mg/g. Kinetic modeling, specifically the pseudo-first-order kinetic model, accurately predicted the adsorption kinetics, yielding a retention capacity of 188.36 mg/g with an adsorption rate of 0.5944 min⁻¹. Furthermore, equilibrium isotherm modeling conclusively demonstrated a superior fit with the Langmuir isotherm, surpassing the Freundlich isotherm, with theoretical Langmuir values reaching 188.67 mg/g. The Dubinin-Radushkevich (D-R) isotherm model provided chemisorption as the dominant process, evidenced by adsorption energy (E_D) of 9.121 kJ/mol and a theoretical retention power of 187.524 mg/g. Additionally, the heat of sorption (b_T) was determined to be 10.252 kJ/mol, closely aligning with the D-R isotherm's adsorption energy, thereby reinforcing the conclusion of a chemisorption-driven process. The provided thermodynamic analysis conclusively demonstrates that the adsorption process is notably exothermic, spontaneous, and thermodynamically favorable at reduced temperatures. Eluting Cd²⁺ ions from the saturated α-AATh, achieving an impressive 99% recovery rate through the application of 2 M H₂SO₄. Furthermore, the composite exhibits remarkable reproducibility, maintaining its robust performance over ten adsorption/elution/scrubbing cycles with negligible capacity loss, boasting an outstanding 99.5% efficiency. Crucially, the efficacy of α-AATh in extracting Cd²⁺ ions from Saudi Arabia's industrial mining discharge wastewater rigorously adheres to the stringent safety standards stipulated by both WHO and FAO guidelines, thereby guaranteeing the potability and safety of the treated water after a single treatment cycle.