Alka Tiwari

Adsorption of Hg(II) Ions onto Binary Biopolymeric Beads of Carboxymethyl Cellulose and Alginate

The removal of Hg(II) ions from aqueous solution by adsorption onto cross-linked polymeric beads of carboxymethyl cellulose (CMC) and sodium alginate was studied at fixed pH (6) and room temperature 28 ± 0.2°C. The cross-linked polymeric beads were characterized by FTIR spectra. Sorption capacity of the polymer for the mercury ions was investigated in aqueous media consisting different amounts of mercury ions (2.5 to 100 mg dm−3) and at different pH values (2 to 8). Adsorption behavior of Hg(II) ions could be modeled using both the Langmuir and Freundlich isotherms. The dynamic nature of adsorption was quantified in terms of several kinetic constants such as rate constants for adsorption (k1) and Lagergreen rate constant (Kad). The influence of various experimental parameters such as effect of pH, contact time, solid-to-liquid ratio, salt effect, and temperature effect etc. were investigated on the adsorption of Hg(II) ions.

Removal of Rhodamine-B from Aqueous Solution by Adsorption onto Crosslinked Alginate Beads

The biosorption of rhodamine-B from aqueous solution using crosslinked alginate beads was studied by contact method at fixed pH −3 and room temperature (28 ± 0.2°C). Both the Freundlich and Langmuir isotherm models could describe the adsorption equilibrium of the rhodamine-B onto crosslinked alginate beads. The influence of various experimental parameters such as pH, temperature, effect of concentration and time were evaluated. It was observed that the adsorption capacity of rhodamine-B onto alginate beads decreased with increase in pH and temperature above room temperature.

Dynamic and Equilibrium Studies on Adsorption of Cu(II) Ions onto Biopolymeric Cross-Linked Pectin and Alginate Beads

Binary biopolymeric beads of alginate and pectin were prepared and characterized by FTIR spectra. On to the surfaces of the prepared beads were performed static and dynamic adsorption studies of Cu(II) ions at fixed pH and ionic strength of the aqueous metal ion solutions. The adsorption data were applied to Langmuir and Freundlich isotherm equations and various adsorption parameters were calculated. The influence of various experimental parameters such as effect of time, pH, temperature, solid to liquid ratio, and the presence of salts were investigated on the adsorption of copper ions.

Removal of Cobalt Ions from Aqueous Solution by Adsorption onto Cross-Linked Calcium Alginate Beads

The removal of cobalt ions from dilute aqueous solutions using cross linked calcium alginate beads as the adsorbent is reported in this article. The influence of various experimental parameters such as pH, initial metal ion concentration, contact time and solid to liquid ratio were studied. The adsorption data were applied to Langmuir and Freundlich isotherm equations and various static parameters were calculated. It was observed that the uptake of cobalt ions was found to increase with time and that maximum adsorption was obtained within the first 60 minutes of the process. These results indicate that the cross linked calcium alginate beads have potential for removing cobalt ions from industrial waste water.

Removal of Chromium(VI) Ions by Adsorption onto Binary Biopolymeric Beads of Sodium Alginate and Carboxymethyl Cellulose

The removal of chromium ions from dilute aqueous solution using biopolymeric beads of cross-linked sodium alginate and carboxymethyl cellulose as the adsorbent is reported in this article. The biopolymeric alginate and carboxymethyl cellulose beads were prepared and characterized by FTIR spectra. On the surface of the prepared beads were performed static and dynamic adsorption studies of chromium ions at fixed pH and ionic strength of the aqueous metal ion solution. The adsorption data were applied to Langmuir and Freundlich isotherm equation and various static parameters were calculated. The dynamic nature of adsorption was quantified in terms of several kinetic constants such as rate constant for adsorption (k1) and Lagergreen rate constant (kad). The influence of various experimental parameters such as pH, time, temperature, solid–liquid ratio, presence of salt, and chemical composition of beads were investigated on the adsorption of chromium ions.

Removal of arsenic ions from aqueous solutions by adsorption onto biopolymeric crosslinked calcium alginate beads

The present article discusses the removal of As (V) ions from dilute aqueous solutions by adsorption onto biopolymeric beads of crosslinked calcium alginate. The beads were characterized by FTIR spectroscopy and their water sorption capacity was investigated. The process of adsorption of arsenic ions was monitored and various adsorption parameters were evaluated. The experiments were conducted to optimize the removal capacity and study the influence of various experimental factors such as pH, initial metal ion concentrations, contact time, and solid-to-liquid ratio. The adsorption data were applied to Langmuir and Freundlich isotherm equations, and various static parameters were calculated.

Efficiency of Superparamagnetic Nano Iron Oxide Loaded Poly(Acrylamide-co-Maleic acid) Hydrogel in Uptaking Cu2+ Ions from Water

A novel superparamagnetic iron oxide nanoparticles loaded poly(acrylamide-co-maleic acid) hydrogel (superparamagnetic PAM hydrogel) has been synthesized and cross-linked by methylene bisacrylamide for the investigation of its efficiency in uptaking copper ions from aqueous solution by batch method. The swelling behavior of the hydrogel was investigated. Metal ion uptake capacity of the adsorbent was evaluated in the light of varying pH, contact time, temperature, adsorbent dose, and different copper ion concentration. The synthesized superparamagnetic PAM was characterized by FTIR and XRD analysis. The structure and coating of the magnetic nanoparticles were characterized by XRD and FTIR analysis respectively. The adsorption data was fitted well in the Langmuir, Freundlich, and Temkin models and various static parameters were calculated. It is stated that this hydrogel could be regenerated efficiently (>97%) and used repeatedly.

Adsorption of Chromium on Composite Microspheres of Chitosan and Nano Iron Oxide

The batch removal of Cr(VI) ions from aqueous solution using binary composite microspheres of chitosan and nanoparticles of iron oxide under different conditions has been investigated in this study. The influences of initial chromium concentration, contact time, pH, temperature, and solid-liquid ratio have been reported. The adsorption data was fitted well in the Langmuir and Freundlich models and various static parameters were calculated. The mechanism of adsorption was studied by Fourier Transform Infrared spectroscopy (FTIR).

Effective removal of Cu2+ ions from aqueous solution in fixed-bed micro column using nanomagnetite-loaded poly (acrylamide-co-maleic acid) hydrogel as adsorbent

AbstractThe efficiency of nanomagnetite-loaded poly (acrylamide-co-maleic acid) hydrogel to remove Cu(II) ions from aqueous solution as well as contaminated water was studied in fixed-bed microcolumn. The effect of bed depth, inlet Cu(II) concentration and feed flow rate on the breakthrough characteristics of the adsorption system were determined in fixed-bed column studies. This study examined the applicability of the various empirical models to determine column dynamics by Thomas, Yoon–Nelson, and Adams–Bohart on copper ions removal from aqueous solution. The adsorbent has been found to be an efficient adsorbent for toxic Cu(II) ions from aqueous solution (>98% removal) and could be regenerated efficiently and used repeatedly for further experiments.

Assessment of Pb2+ ions removal efficiency of nanomagnetite-loaded poly (acrylamide-co-acrylic acid) hydrogel in fixed-bed microcolumn from aqueous solution

AbstractThe adsorption potential of nanomagnetite-loaded poly (acrylamide-co-acrylic acid) hydrogel, to remove Pb(II) ions from aqueous solution as well as contaminated water, was investigated using fixed-bed adsorption column. The effect of inlet Pb(II) concentration, feed flow rate, and bed depth on the breakthrough characteristics of the adsorption system were determined. The adsorption capacity increased with the increase in initial Pb(II) concentration and flow rate, but decreased with increasing bed depth. The Thomas, Yoon–Nelson, and Adams–Bohart kinetic models were applied to the experimental data to predict the breakthrough curves and to determine the characteristic parameters of the column, useful for process design.