Poly(hydroxamic acid) ligand from palm‐based waste materials for removal of heavy metals from electroplating wastewater

Abstract

Heavy metals pollutants are nonbiodegradable and their bioaccumulation results in detrimental environmental consequences. Therefore, it is important to effectively remove toxic heavy metal waste from industrial sewage. Thus, the main goal of this research is to synthesize an ideal cellulose‐based adsorbent from palm‐based waste materials (agro waste) in order to be utilized in real‐life practical applications with low cost as such removing common toxic heavy metals from industrial effluents. A poly(methyl acrylate) grafted palm cellulose was synthesized via a free‐radical initiation process, followed by an oximation reaction to yield poly(hydroxamic acid) ligands. The adsorption capacity (qe) of poly(hydroxamic acid) ligands for metal ions such as copper (Cu2+), iron (Fe3+), and lead (Pb2+) were 325, 220, and 300 mg g−1, respectively at pH 6. In addition, the X‐ray photoelectron spectrometry results are to be proved the binding of metal ions, for instance, Cu(II) ions showed typically significant BEs of 932.7 and 952.0 eV corresponding to the Cu2p3/2 and Cu2p1/2 species. The heavy metal ions adsorption followed a pseudo‐first‐order kinetic model pathway. The adsorption capacity (qm) is also derived from the Langmuir isotherm linear plot, which does not showed good correction coefficients. However, the results were correlated to the Freundlich isotherm model, where the R2 value showed significance (>0.98), indicating that multiple layer adsorption occurs on the synthesized ligand. The synthesized polymeric ligand is an excellent adsorbent for the removal of heavy metals from the industrial wastewater. In addition, the metal analysis results showed that about 98% removal of copper and iron ions from electroplating wastewater including lead, nickel, and chromium can be removed up to 85–97%.

Waste Fiber-Based Poly(hydroxamic acid) Ligand for Toxic Metals Removal from Industrial Wastewater

“…As expected, poly(hydroxamic acid) ligand was derived white in color (navajo white) as referred to previous studied [ 23 , 25 ]. The chelating ligand was prepared by the oximation reaction of acrylate functional groups containing esters of the poly(methyl acrylate)-grafted cellulose in basic condition.…”

“…In this study, a monomer, namely, methyl acrylate was used in the grafting reaction onto cellulose at optimum conditions. According to the methods reported on the graft copolymer reaction, the mixture of cellulose, monomer, and an initiator in a round-bottom flask was constantly agitated and purged with nitrogen gas to create an inert condition in order to get rid of oxygen gas during graft copolymerization reaction [ 22 , 25 ]. The cellulose-grafted copolymer was then converted into chelating ligand, namely, poly(hydroxamic acid), and it was used as the adsorbents in the batch adsorption studies.…”

“…About 10.0 g of poly(methyl acrylate)-grafted cellulose was added into a round-bottom flask with freshly prepared hydroxylamine solution at pH 10. The mixture was heated at 70 °C with stirring for 6 h. The work-up procedure was accomplished by previous work [ 23 , 25 ]. The resulting poly(hydroxamic acid) ligand was dried at 50 °C for 24 h.…”

“…The ligand was regenerated back by washing with water until remaining HCl was removed from the ligand. Then, CH 3 COONa buffer of pH 6 was added with every cycle of adsorption experiment for the reusability test for six cycles of adsorption-desorption process [ 25 ].…”

“…Certainly, the radicals are created on the cellulose (AGU, anhydroglucose unit) resulting in the formation of covalent bonds with the desired monomers; further, in many propagating units, the chains grow until termination process occurs. Ultimately, a grafting copolymer product can be generated via disproportionation step or combination of two growing chains of cellulose molecules [ 23 , 24 , 25 ]. Eventually, there is chemical conversion of the grafted cellulose into the chelating ligands specially hydroxamic acid for the coordination with metals ions in a simple binding system.…”