Adsorbent For Removal Of Cadmium Research Articles

NiFe2O4 magnetic nanoparticles as an adsorbent for cadmium removal from aqueous solution

The magnetic NiFe2O4 nanoparticles have been synthesized and used as adsorbents for cadmium removal from aqueous solution. The NiFe2O4 nanoparticles were characterized by scanning electron microscope (SEM), Transmission electron microscope (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectra (FTIR). Various parameters, which can affect the adsorption such as pH, adsorption time and adsorbent dose have been fully investigated. The results reveal that the magnetic adsorbent can be easily removed by a simple external magnet with high separation efficiency. In addition, the process is clean and safe for purifying water pollution. The prepared NiFe2O4 magnetic nanoparticles could thus be used as favorable adsorbents for the remove cadmium from polluted water.

Carbon nanotubes as sorbent material for removal of cadmium

Heavy metal ions are highly toxic industrial pollutants of which maximum levels are regulated such as in the ppb range for drinking water. Elevated levels of heavy metals in natural water may have a detrimental effect on both human health and the environment. Carbon nanotubes (CNTs) have been investigated widely over last two decades for numerous potential applications to exert considerable technological impact on future miniaturized, compact, cost effective, and efficient devices. The novel tubular structures of CNTs became one of the most valuable materials in water management due to their distinct features such as inertness, porous structure, low density, and affinity for pollutants. Such astonishing features help make them overcome the shortcomings of activated carbon. In this research, we focused on the synthesis, characterization, and evaluation of multi walled carbon nanotubes (MWCNTs) as adsorbent for removal of cadmium. MWCNTs synthesized in size range of 60–70nm (width) and length in microns using chemical vapour deposition (CVD) method were characterized by the field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and Raman spectroscopic analyses. These MWCNTs when explored for the removal of cadmium ions (Cd2+) from their aqueous solutions exhibited a maximum adsorption capacity of 181.8mg/g with the Langmuir isotherm model (R2=0.98). The findings of this research work project that CNTs can play a vital role as nanoadsorbent towards heavy metals management.

Cadmium Removal from Aqueous Solutions Using Dried Banana Peels as An Adsorbent: Kinetics and Equilibrium Modeling

The use of Dried banana peels as an adsorbent for removal of cadmium ions from aqueous solutions has been studied. Batch experiments have been conducted at different concentrations to evaluate the maximum adsorption capacity of Dried banana peels. The influence of pH, contact time, adsorbent dose was investigated at room temperature. Langmuir and Freundlich adsorption isotherm models used to test equilibrium of adsorption. The process of adsorption was found to be fast and equilibrium has been reached in within 2 hours. The maximum adsorption capacity of cadmium on Dried banana peels is 5.91 mg/g, evaluated by Langmuir adsorption isotherm model. Pseudo-first-order and pseudo-second-order kinetic models applied to evaluate rate constants. FTIR spectra of adsorbent showed the presence of hydroxyl, carboxylic and amine groups in dried banana peels. This study shows that banana peels has great potential for removal of cadmium ions and can be used as a good adsorbent for removal of cadmium from water and wastewater at very low concentration.

Adsorptive Removal of Cadmium and Lead from Oryza Sativa Rice by Banana Peel as Bio-Sorbent

Adsorptive Removal of Cadmium and Lead from Oryza Sativa Rice by Banana Peel as Bio-Sorbent

Comments on “Adsorptive removal of cadmium(II) ions from liquid phase using acid modified carbon-based adsorbents”

Comments on “Adsorptive removal of cadmium(II) ions from liquid phase using acid modified carbon-based adsorbents”

Effect of pH and Calcium on the Adsorptive Removal of Cadmium and Copper by Iron Oxide–Coated Sand and Granular Ferric Hydroxide

AbstractIron oxide–coated sand (IOCS) and granular ferric hydroxide (GFH) were used to study the effect of Ca2+ and pH on the adsorptive removal of Cu2+ and Cd2+ from groundwater using batch adsorption experiments and kinetic modeling. It was observed that Cu2+ and Cd2+ were not stable in synthetic waters. The extent of precipitation increased with increasing pH. Removal of Cu2+ and Cd2+ was achieved through both precipitation and adsorption, with IOCS showing higher adsorption efficiency. Increase of pH (from 6 to 8) resulted in a higher overall removal efficiency of both Cu2+ and Cd2+, with precipitation as predominant removal mechanisms at higher pH values, especially for Cu2+. An increase in Ca2+ concentration increased the precipitation of Cu2+ [as Cu2(OH)2CO3 and Cu3(OH)2(CO3)2] and Cd2+ [as Cd(OH)2 and CdCO3]. In addition, Ca2+ competes with Cu2+ and Cd2+ for surface adsorption sites on IOCS and GFH, and reduces their adsorption capacity. The kinetic modeling revealed that the adsorption of Cd2+ on...

Immobilisation of TiO2-nanoparticles on sewage sludge and their adsorption for cadmium removal from aqueous solutions

In this study, pure TiO2-nanoparticles and TiO2/sewage sludge (TS) as biomass material were synthesised via a sol–gel method. The adsorption potential of nanosized TiO2 and TS for removal of Cd(II) was investigated in a batch system. The prepared adsorbents were characterised using X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The XRD analysis showed that pure TiO2 is in amorphous phase before calcination and in anatase phase at annealing temperature of 400 °C. TiO2/sewage sludge that calcined at 400 °C (TS400) was found to be the best adsorbent for cadmium removal from aqueous solution. Kinetic and isotherm studies were carried out by considering the parameters, pH, initial concentration and contact time. The optimum pH value for Cd(II) adsorption onto TS400 was found to be 6. Langmuir isotherm showed better fit than Freundlich isotherm and the maximum adsorption capacity was found to be 29.28 mg/g which is higher than that of many other adsorbents reported in literature. The sorption kinetic data were well fitted with a pseudo-second-order model. These results demonstrated that TS400 was readily prepared and is the promising and effective solid material for the removal of Cd(II) from aqueous solutions.

Adsorptive removal of cadmium(II) ions from liquid phase using acid modified carbon-based adsorbents

This work reports a comprehensive study of the adsorption characteristics of cadmium(II) on modified structures of carbon nanotubes (CNTs), carbon nanofibres (CNFs), activated carbon (AC), and fly ash (FA). The characterization was performed using field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA) and Brunauer–Emmett–Teller (BET) surface analysis. Several experimental parameters; adsorbent dosage, pH, and agitation speed and contact time, were investigated for their effects on the adsorption of cadmium(II) from water. The optimum conditions of 2h of contact time, pH7, 50mg adsorbent dosage and 150rpm rotational speed were observed. Models of first-order, second-order and pseudo-second-order were fitted to the experimental data, and pseudo-second-order kinetics were observed to describe the adsorption of cadmium(II) on these adsorbents. The adsorption behaviours of cadmium(II) were evaluated using the Freundlich and Langmuir isotherm models. The maximum adsorption capacities of the modified adsorbents were observed to be 2.02mg/g, 1.98mg/g, 1.22mg/g and 1.58mg/g, for CNTs, AC, CNFs and FA, as obtained from Langmuir isotherm models. It was determined that surface modification of the CNTs, CNFs, and AC enhanced their adsorption efficiency. The results obtained are promising for the use of these modified materials with respect to water purification applications.

Adsorption of cadmium onto modified nanosized magnetite: kinetic modeling, isotherm studies, and process optimization

In this study, adsorptive removal of cadmium(II) from aqueous solutions using sodium dodecyl sulfate-modified magnetite nanoparticles was modeled. To this aim, central composite design as one of the most favorable designs in response surface methodology (RSM) was employed to optimize the removal of Cd(II) from solution under different variables such as adsorbent dosage (0.1–0.55 g), initial ion concentration (6–90 mg/L), and reaction time (5–30 min). Furthermore, the experimental data of Cd(II) adsorption were tested with various kinetic and isotherm models at various initial ion concentrations of 10–50 mg/L and adsorbent dosages of 0.1–0.25 g. The adsorption process followed the intra-particle diffusion model (R2 > 0.94) very well. The equilibrium adsorption data were analyzed using various isotherm models. The results showed that Freundlich isotherm, with a relatively high coefficient of determination (R2 > 0.96), fits well with the experimental results of Cd(II) adsorption. Ultimately, the optimum Cd(II) ions removal of 91.07% was obtained at the reaction time of 30 min, the adsorbent dosage of 0.35 g, and the initial ion concentration of 30 mg/L.

Cd(II) removal and recovery enhancement by using acrylamide–titanium nanocomposite as an adsorbent

Abstract Acrylamide (AM) was in-situ doped into titanium during sol–gel reaction and used as an adsorbent for cadmium removal from aqueous solution. The resulting TiO 2 -AM nanocomposite was characterized by particle size distribution (PSD) and thermogravimetric analysis (TGA). After cadmium adsorption, the nanocomposite was also characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy/energy-dispersive X-ray (SEM/EDX) and X-ray photoelectron spectroscopy (XPS) analyses. The adsorption behavior of the nanocomposite was examined by kinetic and equilibrium studies in batch conditions. The maximum cadmium binding capacity of TiO 2 -AM was 322.58 mg g −1 at an optimum pH of 8.0, compared to 86.95 mg g −1 for nano-titanium. Cadmium sorption showed pseudo-second-order kinetics with a rate constant of 4.0 × 10 −4 and 9.4 × 10 −5 g mg −1 min −1 at an initial Cd(II) concentration of 100 and 500 mg L −1 , respectively. Cd (II) adsorption interference of cations (Pb 2+ , Cu 2+ , Co 2+ and Zn +2 ) and anions (Cl − , SO 4 2− , CO 3 2− ) at pH 8 was very nominal because of favorable complex formation of Cd(II) and amide. The Cd(II) adsorption of 27% that was achieved in the fifth cycle was regenerated with 0.05 N acidic solutions.

RETRACTED ARTICLE: Adsorptive removal of cadmium from aqueous media using Posidonia oceanica biomass: equilibrium, dynamic and thermodynamic studies

Posidonia oceanica (L.), a marine biomass, has been used as an effective and efficient biosorbent for the removal of Cd(II) from aqueous media. The physico-chemical properties of biosorbent were investigated by elemental analysis, BET surface area, FT-IR, SEM and EDX methods before and after adsorption. Batch adsorption experiments were carried out to investigate the effects of solution pH, dosage of biosorbent, contact time and temperature. The biosorbent exhibited the maximum uptake of 58.82 mg/g under the optimal adsorption condition. Kinetics experiments indicated that the pseudo-second-order model displayed the best correlation with adsorption kinetics data. Besides, experimental data could be better described by the Langmuir isotherm model. Desorption experiments were carried out to explore the feasibility of regenerating the biosorbent. The regeneration efficiency was 96.03 % using desorption agent of 0.2 M HCl. The thermodynamic parameters (ΔH0, ΔS0 and ΔG0) of the cadmium ion uptake onto P.O indicated that the process is endothermic and proceeds spontaneously. The findings of the present study indicate that P.O can be successfully used for separation of Cd(II) from aqueous solutions. The results suggested that the adsorbent is promising for use as an effective and economical adsorbent for Cd(II) ions removal.

Removal of Cadmium from Water Using Natural Phosphate as Adsorbent

Adsorption process is being widely used by various researchers as an effective process of advanced waste water treatment of industrial effluent containing metals. The present work involves an investigation of the use of natural phosphate (NP), which being locally abundant and cheap material in Morocco, as adsorbent for removal of cadmium from aqueous solutions. The kinetic of Cadmium on natural phosphate adsorption efficiency and adsorption process were evaluated and analyzed using Langmuir and Freundlich model of adsorption equilibrium. The effects of various experimental parameters, such as initial cadmium concentration, contact time were investigated. The natural phosphate had the monolayer adsorption capacity to 26mg/g at pH of 5.0. Adsorption measurements show that the process is very fast and physical in nature. The extent of the cadmium removal increase with decrease in the initial concentration. These results show that natural phosphate is a good adsorbent for cadmium from aqueous solutions and could be used as a purifier for water and wastewater.

Removal of Cadmium Ion from Water/Wastewater by Nano-metal Oxides: A Review

Environmental water samples contain wide range of contaminants including heavy metal ions that are required only in trace amount. Excessive level of metal ions in water may be detrimental to health and environment. Heavy metal poisoning has been a serious concern all over the globe. Heavy metals are well known to be non-biodegradable and tend to bio-accumulate at various concentrations. A number of methods have been proposed to remove heavy metal ions from water and among them adsorption is one of the best methods. Cadmium has been identified as one of the toxic heavy metals that enters the water through disposal of waste from industries. The increasing technological use of cadmium has raised the concern for its removal from water/wastewater. This review article provides an overview of use of nano-metal oxides as adsorbents for removal of cadmium from water/wastewater. This study involves the identification of environmentally friendly, low-cost and efficient nano-metal oxide sorbents for water/wastewater purification. A detailed comparison of reported nano-metal oxide sorbents has been done in order to rank them and to predict the knowledge gaps in this area.

Spectroscopic and computational evaluation of cadmium adsorption using activated carbon produced from rubber tires

The aim of this work was to investigate the utilization of waste tire carbons as a low cost adsorbent for removal of cadmium (II) ion from aqueous solution with density functional theory calculations to shed more light on the adsorption process. Thus, activated carbon was prepared from waste rubber tires and characterized by means of field emission scanning electron microscopy, energy-dispersive X-ray and Fourier transform infrared spectroscopies. Effect of various operating parameters like contact time, dosage, agitation speed and pH on the removal of Cd(II) from aqueous solution by the batch adsorption technique was investigated. The adsorption process was relatively fast and the equilibrium was reached after about 60min of contact. Characterization of activated carbon after adsorption was also conducted. Density functional theory (DFT) calculations were performed to estimate the binding energy of Cd2+ ions towards carboxylic acid, carbonyl and hydroxyl groups. The calculated binding energy of the adsorption process was predicted to be in the range of 190–212kcal/mol, and the Cd2+ ion tends to approach more conveniently towards the carbonyl's oxygen atom in the carboxylic acid and carbonyl groups. The developed sorbent exhibited the advantages of being inexpensive and of double benefit to the environment.

Silkworms’ feces-based activated carbons as cheap adsorbents for removal of cadmium and methylene blue from aqueous solutions

Activated carbon samples, ACs, were obtained from silkworms’ feces via chemical activation method. Many activating agents including the new ones KCl, CrCl3 and TiCl4 were compared. Acidic and basic oxidic groups in addition to aromatic tertiary and secondary amines have been detected on the surface of produced ACs. Furthermore, microporous solids furnishing high internal specific surface area, ranging between 1000 and 2000m2/g, and total pore volume up to 0.85cm3/g were obtained. TiCl4 resulted in the solid possessing the highest area and pore volume. The obtained solids showed high efficiency in removing methylene blue and cadmium from their aqueous solutions. Adsorption capacity of sample AC/TiCl4 is 461mg/g of MB at pH=10, and 62.6mg/g of Cd2+ at pH=8. The nature of the formed microporous texture and the prevailing surface oxidic groups are the main controlling parameters for the observed high efficiency toward both adsorbates.

Fixed Bed Column Adsorption Studies Using Fly Ash for Removal of Cadmium from Aqueous Solution

In the present paper, adsorptive removal of cadmium from synthetic wastewater using a 2 cm diameter fly ash column was studied through three column adsorption experiments by varying column depths (10, 15 and 20 cm). Study results showed fly ash to be an effective adsorbent for cadmium removal. Column design parameters such as depth of adsorption zone (6 cm), critical bed depth (1.3 cm), adsorption capacity (480.82 mg/l) and adsorption rate constant (0.0111 l/mg min) are calculated using bed depth service time approach. Using the same method effect of varying flow rate (5, 8 and 10 ml/min) and initial cadmium concentration (15 and 20 mg/l) was studied and the corresponding model predicted service times conformed well with the experimentally obtained results from three more column studies. Negligible leaching of adsorbed cadmium from exposed fly ash column was observed during two desorption studies.

Adsorptive Removal of Cadmium and Copper from Water by Mesoporous Silica Functionalized with N-(Aminothioxomethyl)-2-Thiophen Carboxamide

Copper and cadmium ions were removed from aqueous solutions by adsorption onto a new organic-inorganic hybrid material. N-(aminothioxomethyl)-2-thiophen carboxamide (TAC) was covalently anchored on SBA-15 mesoporous silica. Various characterization techniques [X-ray diffraction, nitrogen adsorption-desorption, thermogravimetric analysis, Si29, C13 nuclear magnetic resonance (NMR), and Fourier-transform infrared (FTIR) spectroscopy] have proved that the organic ligand was successfully anchored and the ordering of the inorganic support was preserved during the chemical modifications. Metal cations in aqueous solution were adsorbed onto this material with multichelating atoms by a complexation mechanism. Adsorption capacity for the divalent copper and cadmium cations were 0.74 and 0.21 mmol g−1, respectively. Cu(II) was selectively eliminated from contaminated water with Cu(II) and Cd(II). TAC-functionalized silica sorbent presented a good regeneration capacity without significantly losing its adsorption capacity and could be used for the development of an in-flow wastewater purification technology.

Application of dried plant biomass as novel low-cost adsorbent for removal of cadmium from aqueous solution

Heavy metals are a threat to human health and ecosystem. These days, great deal of attention is being given to green technologies for purification of water contaminated with heavy metal ions. Biosorption is one among such emerging technologies, which utilizes naturally occurring waste materials to sequester heavy metals from wastewater. Cadmium has hazardous impact on living beings; therefore, its removal through green and economical process is an important task. The aim of the present study was to utilize the locally available Portulaca oleracea plant biomass as an adsorbent for cadmium removal from aqueous solution. The biomass was obtained after drying and grinding the portulaca leaves and stem. No chemical treatment was done on the adsorbent so that it remained green in a true sense. Batch experiments were performed at room temperature. The critical parameters studied were effects of pH, contact time, initial metal ion concentration and adsorbent dose on the adsorption of cadmium. The maximum adsorption was found to be 72 %. The kinetic data were found to best fit the pseudo-second-order equation. High adsorption rates were obtained in the initial 45 min, and adsorption equilibrium was then gradually achieved in about 100 min. Adsorption increased with increase in pH for a range 2 and 6. The equilibrium adsorption results closely followed both the Langmuir and Freundlich isotherms. The values of constants were calculated from isotherms. Results indicated that portulaca plant biomass could be developed as a potential material to be used in green water treatment devices for removal of metal ions.

Adsorptive removal of cadmium (II) using P. oceanica biomass: effect of NaCl concentration on equilibrium and kinetic parameters

In this study, biosorption of cadmium (II) from saline solutions by Posidonia oceanica (L.), a marine biomass, was studied as a function of pH, initial cadmium (II) and NaCl concentrations in a batch system. The sorbent exhibited the maximal cadmium (II) uptake at pH 6 in the absence and in the presence of increasing concentration of NaCl. Equilibrium uptake increased with the cadmium (II) concentration up to 250 mg/L and diminished considerably in the presence of increasing concentrations of salt up to 50 g/L. At 100 mg/L, initial cadmium (II) concentration, P. oceanica biosorbed 15.69 mg/g of cadmium (II) without salt medium. When NaCl concentration was raised to 50 g/L, this value dropped to 6.87 mg/g of cadmium (II) at the same conditions resulting in 56.21% decrease in biosorption capacity. The equilibrium sorption data were analysed by using Freundlich, Langmuir and Redlich–peterson models. Langmuir was the most suitable adsorption model for describing the biosorption equilibrium data of cadmium (II) both individually and in salt-containing medium. Pseudo-second-order kinetic model also fitted well to both systems, viz. cadmium (II) and cadmium (II) + NaCl. Isotherm constants varied due to the level of salt were expressed as a function of initial NaCl concentration.

Biosorption of Cadmium from Water Using Moringa (Moringa oleifera Lam.) Seeds

This study aimed to evaluate the efficacy of using the byproduct of Moringa oleifera Lam. seeds as an adsorbent for removal of cadmium (Cd) from contaminated water. The material characterization was performed by scanning electron microscopy, infrared spectroscopy, and point of zero charge. The effects of the adsorbent mass, solution pH, contact time, and temperature were evaluated. In the preliminary studies, the mass of adsorbent (200–1200 mg) and pH conditions (5.0, 6.0, and 7.0) were varied. The time studies were performed at 20–180 min and the temperature studies at the range of 25–65 °C. The optimal conditions of adsorption obtained were 400 mg of adsorbent mass, 7.0 pH, and 160 min contact time with the adsorbent. The isotherms of adsorption were linearized according to Langmuir, Freundlich, and Dubinin–Radushkevich (D-R) models. The results showed better fit by the Freundlich and D-R models for Cd adsorption, describing a multilayer adsorption and, according to the value of the sorption energy (E), it has chemical nature. The maximum capacity of adsorption (Q m) obtained was 7.864 mg g−1. For a comparative study, the activated carbon (P.A.) was used applying the same optimal conditions used in the adsorption isotherms and desorption process for the biosorbent, obtaining a Q m as 32.884 mg g−1. The average desorption percentage showed that adsorbents have strong interaction with the metal. Based on these results, it was concluded that the biosorbent was effective in remediation of solutions containing Cd and thus the use of this alternative material is a viable option, since it has low cost and it is a byproduct which has not undergone previous treatment.