Aliquat 336-functionalized metal-organic frameworks: An innovative strategy for the removal of trace lead ions

Clean water is essential for all life, and lead (Pb) contamination continues to be a major concern due to its persistence, toxicity, and tendency to bioaccumulate. Effective and durable removal methods are required even at trace Pb(II) levels. For this, adsorption has become a straightforward, affordable, and efficient technique. utilizing hydroxyethylidene-1,1-diphosphonic acid (HEDP), zinc and copper phosphonate-based metal-organic frameworks (Zn HEDP and Cu HEDP) were created in this study utilizing environmentally friendly methods. The ionic liquid trioctylmethylammonium chloride (Aliquat 336) was then used to functionalize them, which were specifically referred to as Zn HEDP-US Aliq. and Cu HEDP-US Aliq., respectively. Aliquat 336 increased experimental maximum adsorption capacities by 40.8% for Zn HEDP and 27.65% for Cu HEDP by improving surface functionalization, charge density, and Pb(II) adsorption efficiency while maintaining the crystalline framework, according to structural characterisation. In addition to boosting porosity, adsorption capacity, and regeneration potential, ionic liquid functionalization added more active sites and enhanced surface homogeneity, allowing for stronger and more selective binding of Pb(II) even at low concentrations. According to UN SDG 6.3, these results show that ionic liquid-functionalized MOFs are effective, reusable, and sustainable adsorbents for trace metal remediation, promoting environmentally friendly water purification.