Cadmium (Cd(II)) ion is one of the most important toxic metals to remove from contaminated water for safe-guarding the public health. Elevated levels of Cd(II) ion in natural water may have a detrimental effect on both human health, environment and the eco-system. The functionalized materials have been investigated widely over the years for numerous uses to exert a considerable technological impact on future miniaturized, compact, cost effective, and efficient devices. From this point of view, the functional ligand based composite material was fabricated based on the direct anchoring methods for effective Cd(II) ion detection and removal from wastewater. The significant color was visualized upon addition of Cd(II) ion at optimum condition. The optimum pH was carefully evaluated, and pH 5.50 was selected based on the sensitivity, selectivity and color formation. The detection limit was 0.37 μg/L, which was lower than the permissible limit of Cd(II) ion in water. The variable experimental parameters such as solution pH, initial concentration, contact time and foreign ions were systematically evaluated both in monitoring and adsorption operations. The adsorption data were well fitted to the Langmuir adsorption model, and the maximum adsorption capacity was 186.36 mg/g. In the presence of competing ions, the Cd(II) detection and adsorption were not affected due to the specific binding affinity between the composite material and Cd(II) ions. The adsorb Cd(II) ion was desorbed from the composite material using 0.15 M HCl, and the material were simultaneously regenerated into the initial form for the next cycle use without loss the functionality.

A facile composite material for enhanced cadmium(II) ion capturing from wastewater

Organic ligand based sustainable composite material was prepared for the detection and removal of nickel (Ni(II)) ion from contaminated water. The ligand was anchored based on the building-block approach. The carrier silica and ligand embedded composite material were characterized systematically. The detection and removal of Ni(II) ion operation was evaluated according to the solution pH, reaction time, detection limit, initial Ni(II) concentration and diverse co-existing metal ions. The detection limit of Ni(II) ion by the proposed composite material was 0.41 μg  L−1. The detection and removal of Ni(II) ion was significantly influenced by the solution pH. However, the neutral pH 7.0 was chosen for sensitive and selective detection and removal of Ni(II) ion. The co-existing diverse metal ions were not interfered during the detection and removal of Ni(II) ion because of the high affinity of Ni(II) ion to composite material at the optimum experimental conditions. The Langmuir adsorption isotherm model was selected based on the materials morphology and applied to validate the adsorption isotherms according to the homogeneous ordered frameworks. The adsorption capacity was 199.19 mg g−1 as expected due to the high surface area of material. The adsorbed Ni(II) ion was completely eluted from the composite material with the eluent of 0.50 M HCl and the regenerated material was used in several cycles without deterioration in its initial performances. Therefore, it is expected to that the Facile composite material may hold huge potentials in applications and may be scaled up for commercial applications, including environmental detection and removal of Ni(II) ion.

Ligand based sustainable composite material for sensitive nickel(II) capturing in aqueous media

Waste materials for wastewater treatment and waste adsorbents for biofuel and cement supplement applications: A critical review

Metal oxide-cellulose nanocomposites for the removal of toxic metals and dyes from wastewater.

Sustainable ligand-modified based composite material for the selective and effective cadmium(II) capturing from wastewater

Bioresources are renewable raw materials which can be utilised for multiple purposes including the development of various materials for water treatment. In this study, cellulose nanocrystals (CNC) derived from sawdust was modified and utilised as coagulants for the removal of Ni2+ and Cd2+ ions from water. The modified CNC was characterized using Fourier transform infra-red, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and zeta potentiometer. Analyses revealed that the modified CNC is porous and exhibited narrow particle size distribution and needle-like morphology. The functional group responsible for the coordination and removal of the metals was mainly carboxylate anion (COO2−). Zeta potential measurement showed a reduction in negative surface charge value of modified CNC. The effects of solution pH, CNC coagulant dosage and initial metal concentration were investigated using jar test experiment. Results revealed that the removal of metal ions increased with an increase in the coagulant dosage and solution pH, and that the best pH for the investigation was pH 7.10. Metal removal efficiency, however, reduced with an increase in the initial concentration of the metal ions. Experimental uptake values of 956.6 mg Ni/g and 2207 mg Cd/g were obtained, which in comparison with uptake values of other cellulosic materials gives indication that CNC derived from sawdust is highly competitive material for the amelioration of water containing metals.

Bongani Mutesse

Papers

Highly efficient removal of nickel and cadmium from water using sawdust-derived cellulose nanocrystals