Adsorption Behavior Of Cadmium Research Articles

Influence of Graphene oxide on cadmium concentration in maize plant: implications for contaminant uptake and remediation strategies

ABSTRACT The use of Graphene Oxide (GO) for heavy metal remediation in soil and plants shows great potential for its efficiency, selectivity, and low environmental impact. This study presents the results of a pot experiment investigating the adsorption behaviour of Cadmium (Cd) on GO and the effects of Cd and GO on soil pH, biomass production, and Cd concentration in maize plants. The study found that the pseudo-second-order model was the most suitable model to describe the adsorption behaviour of Cd on GO, followed by the Lagergren model. Results indicated that both Cd and GO have significant effects on soil pH, with GO having a positive and Cd having a negative effect. GO was found to mitigate the negative effects of Cd on biomass, with acting as a chelating agent to reduce the toxicity of Cd and improve nutrient uptake in maize plants. Study found that the GO resulted in a significant increase in chlorophyll content in maize plants, while Cd were found to increase Cd concentration in roots and shoots. Results suggest that GO has the potential to be used as a soil amendment to mitigate the negative effects of Cd on soil and plant health.

Drought-resistant and water-retaining tobermorite/starch composite hydrogel for the remediation of cadmium-contaminated soil

The objective of this work is utilizing fly ash to synthesize tobermorite (TOB) with a higher specific surface area and layered structure, and incorporating it into the starch/acrylic acid network to boost the drought resistance, water retention and heavy metal adsorption properties. The water absorption and water retention performance and cadmium adsorption characteristics of tobermorite/leftover rice-based composite hydrogel (TOB@LR-CH) were evaluated by water absorption swelling test, soil evaporation test and batch adsorption experiment. By adjusting the addition of TOB and other synthesized conditions, the swelling property (from 114.80 g/g to 322.64 g/g), water retention (71.80 %, 144 h) and Cd2+ adsorption characteristics (up to 591.36 mg/g) were significantly enhanced. Adding a moderate amount of TOB (2 wt%) provided the most uniform tobermorite dispersion during synthesis, and TOB2@LR-CH exhibited the most stable three-dimensional network and highest proportion of effective TOB. The adsorption behavior of cadmium on TOB2@LR-CH was more consistent with the pseudo-second-order kinetics and Langmuir isotherm models. Additionally, the regeneration test results displayed that the adsorption removal rate of cadmium by TOB2@LR-CH adsorbent remained stable after 5 cycles. This study demonstrates that TOB@LR-CH has good water absorption and water retention potential in arid and semi-arid soils, and also has potential application prospects in remediating Cd(II)-contaminated soil.

Study on the Adsorption Behavior of Cadmium by the MPs and Its Environmental Factors

Study on the Adsorption Behavior of Cadmium by the MPs and Its Environmental Factors

Adsorption mechanism of cadmium on polystyrene microplastics containing hexabromocyclododecane

There are few studies on the adsorption of heavy metals by microplastics containing additives in water environment. The present study investigated the adsorption mechanism of Cd(II) on polystyrene microplastics containing hexabromocyclododecane (PS-HBCD MPs). In the experiments, the effects of pH value, salinity, particle size and dissolved organic matter derived from PS-HBCD MPs on the adsorption capacity were analyzed. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to analyze the properties of PS-HBCD MPs and adsorption behavior of Cd(II) onto MPs. The adsorption kinetics and isotherms of Cd(II) onto PS-HBCD MPs can be described well by the pseudo-second-order kinetics model and Langmuir isotherm model, respectively. Solution pH, salinity, dissolved organic matter derived from MPs and particle size have a greater impact on the adsorption behavior of cadmium on microplastics. The results of this study highlight the importance of C-Br bonds of PS-HBCD MPs in controlling the adsorption of Cd(II). • Cd(II) adsorption onto PS-HBCD MPs was dominated by electrostatic interaction. • The C-Br bonds of PS-HBCD MPs controlled the adsorption of Cd(II). • DOM derived from MPs inhibited the adsorption of Cd(II) on PS-HBCD MPs

Quantitative studies of cadmium ion (Cd2+) adsorption on oxidized graphite powder

Abstract The adsorption behavior of cadmium (Cd(II)) on surface of oxidized graphite was investigated as a function of concentration of Cd(II), contact time and the amount of oxidized carbon used. Square wave anodic stripping voltammetry was used to measure the uptake of Cd(II). Standard addition method was used to determine the amount of Cd(II) concentration. The adsorption of Cd(II) on oxidized graphite was characterized by X-ray photo electron spectroscopy. Adsorption capacity of bare graphite was found to be 37.37%, where as that of oxidized graphite was 67.6% when 10.0 ml of 100 µM Cd(II) was used with 100 mg of both samples.

Adsorption characteristics of cadmium ions from aqueous solution onto pine sawdust biomass and biochar

The adsorption capacity of cadmium ions by pine sawdust biomass and biochar was evaluated in batch experiments. Pine sawdust biochars were pyrolyzed at 500 °C and 700 °C and obtained in the absence of oxygen. The adsorption capacity of biochar was higher than the raw biomass (3.47 mg/g). Biochars produced at 700 °C showed better adsorption efficiency (6.09 mg/g) than that produced at 500 °C (4.78 mg/g). Also, the adsorption kinetics and adsorption isotherms were studied. The adsorption behavior of cadmium by pine sawdust biomass and biochar fitted Langmuir isotherms and pseudo-second order kinetics. In addition, the desorption experiment by different solutions (neutral, acidic, and alkaline) were conducted. The desorption of cadmium ions in neutral and alkaline environments was not obvious, while the desorption in an acidic environment was. Pine sawdust biochar, pyrolyzed at 700 °C, is a potential adsorbent for cadmium removal in neutral and alkaline environments.

Study on the adsorption behavior of cadmium, copper, and lead ions on the crosslinked polyethylenimine dithiocarbamate material.

In order to obtain a highly efficient solid-state heavy metal ion absorbing material, the crosslinked polyethylenimine dithiocarbamate was prepared via condensation of polyethyleneimine (PEI) with abundant amino groups and glutaraldehyde to form the crosslinked polymer, reduction of the resulting C=N double bonds to a much stable C-N single bonds, and then grafted with carbon disulfide. The material was evaluated in adsorbing cadmium (II), copper (II), and lead (II) ions. The adsorption behavior of cadmium, copper, and lead ions on the absorbent material was studied. Experiment results show that the adsorption rate is rapid for heavy metal ions, and the adsorption amount tends to constant after 40min. Its absorption capabilities for cadmium (II), copper (II), and lead (II) ions reach up to 205.99, 215.02, and 451.79mg/g, respectively. Furthermore, the absorbing material has good desorption and regeneration performance. The adsorption kinetics model well accords with the pseudo-second order kinetic equation. And the process of the adsorption is linear with the Langmuir adsorption model, and thus the adsorption process is monolayer adsorption.

Adsorptive Removal of Cadmium (II) from Aqueous Solution by Multi-Carboxylic-Functionalized Silica Gel: Equilibrium, Kinetics and Thermodynamics

In the present study, the adsorption behavior of cadmium (II) ion from aqueous solution onto multi-carboxylic-functionalized silica gel (SG-MCF) has been investigated in detail by means of batch and column experiments. Batch experiments were performed to evaluate the effects of various experimental parameters such as pH value, contact time and initial concentration on adsorption capacity of cadmium (II) ion. The kinetic data were analyzed on the basis of the pseudo-first-order kinetic and the pseudo-second-order kinetic models and consequently, the pseudo-second-order kinetic can better describe the adsorption process than the pseudo-first-order kinetic model. Equilibrium isotherms for the adsorption of cadmium (II) ion were analyzed by Freundlich and Langmuir isotherm models, the results indicate that Langmuir isotherm model was found to be credible to express the data for cadmium (II) ion from aqueous solution onto the SG-MCF. Various thermodynamics parameters of the adsorption process, including free energy of adsorption (ΔG0), the enthalpy of adsorption (ΔH0) and standard entropy changes (ΔS0), were calculated to predict the nature of adsorption. The positive value of the enthalpy change and the negative value of free energy change indicate that the process is endothermic and spontaneous process.

Adsorption kinetic and desorption studies of Cd2+ on Multi-Carboxylic-Functionalized Silica Gel

In the present study, the adsorption behavior of cadmium (II) ion from aqueous solution onto multi-carboxylic-functionalized silica gel (SG-MCF) has been investigated in detail by means of batch and column experiments. Batch experiments were performed to evaluate the effects of contact time on adsorption capacity of cadmium (II) ion. The kinetic data were analyzed on the basis of the pseudo-first-order kinetic and the pseudo-second-order kinetic models and consequently, the pseudo-second-order kinetic can better describe the adsorption process than the pseudo-first-order kinetic model. And the adsorption mechanism of the process was studied by intra-particle and film diffusion, it was found out that the adsorption rate was governed primarily by film diffusion to the adsorption onto the SG-MCF. In addition, column experiments were conducted to assess the effects initial inlet concentration and the flow rate on breakthrough time and adsorption capacity ascertaining the practical applicability of the adsorbent. The results suggest that the total amount of adsorbed cadmium (II) ion increased with declined flow rate and increased the inlet concentration. The adsorption-desorption experiment confirmed that adsorption capacity of cadmium (II) ion didn’t present an obvious decrease after five cycles.

Adsorption Behavior of Cadmium on Husk of Lentil

Abstract The adsorption behavior of cadmium on husk of lentil an agro-waste was investigated to understand the mechanism of adsorption as well as to explore its potential in removing cadmium from its aqueous solution. The adsorption process of lentil husk (LH) was found to be a function of pH of the solution, optimum being 5.0. The rate of adsorption of cadmium by LH was very fast initially and attained equilibrium within 60 min following pseudo second order rate kinetics. The study established that 1.0 g LH can adsorb 107.31 mg of cadmium and was successful to reduce the concentration of this metal from the effluent of battery industries. Adsorption process followed Langmuir isotherm model with uniform distribution of metal ions on the surface of the biomass as revealed from X-ray elemental mapping. In binary system the biomass displayed a preference in adsorption of lead over cadmium. The results of Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), chemical modification of functional groups and zeta potential measurement established the binding of cadmium to the biomass through electrostatic and complexation reactions.

Removal of cadmium(II) from aqueous solution by adsorption onto modified algae and ash

Pollution with cadmium ions has serious negative consequences on human health and environment. Adsorption of low-cost materials represents a viable option for the removal of cadmium ions from aqueous media. In this study are comparatively discussed the adsorption behaviour of cadmium(II) on two low-cost materials, one of biologic nature (marine algae) and other of inorganic nature (ash), after their treatment with alkaline solution. The influence of contact time and initial cadmium ions concentration was studied in batch system, for each type of adsorbent. In optimum experimental conditions (solution pH of 5.0; adsorbent dose of 8 g L−1 ) and an initial cadmium concentration of 360mg L−1, the obtained uptake capacities reach to 34.15mg g−1 for the modified algae and to 43.12mg g−1 for the modified ash, respectively. The uptake data were analyzed using two isotherm models (Langmuir and Freundlich) and the models’ parameters were evaluated. The results indicate that t heLangmuir model provides the best correlation of experimental data for both adsorbents, and the maximum adsorption capacities were 41.8mg g−1 for modified algae and 48.0 mg g−1 for modified ash, respectively. The kinetics of the cadmium uptake was modelled using the pseudofirst order, pseudo-second order and intra-particle diffusion model equations. It was shown that the pseudo-second order kinetic equation could best describe the adsorption kinetics of cadmium ions, whatever the nature of adsorbent.

Effect of ageing on surface charge characteristics and adsorption behaviour of cadmium and arsenate in two contrasting soils amended with biochar

Biochar has been recognised as an effective amendment for the remediation of contaminated soils; however, there is limited knowledge on the effects of biochar ageing in soil on its adsorption behaviour for cationic and anionic species. Biochars are considered to develop negative charge from oxidation with ageing, which may create additional interaction mechanisms for adsorption processes. In the present study, surface charge characteristics and cadmium (Cd) and arsenate (AsO43–) adsorption behaviour of aged biochar were investigated in two soils with variable charge, an Oxisol and an Inceptisol, by comparing (i) unamended soils, and soils amended with (ii) fresh biochar (450°C) and (iii) biochar (450°C) aged for 12 months, applied at a rate of 2% w/w. Surface charge characteristics were assessed using the ‘index’ ion adsorption method, with a LiCl electrolyte. Batch adsorption studies were conducted using fresh and aged soil–biochar mixtures. In contrast to previous studies, the results provided no evidence of an increase in cation exchange capacity as a consequence of biochar ageing. There was an increase in Cd adsorption in the presence of aged biochar in both soil types compared with unamended soils and soils amended with fresh biochar. Results also indicated an increase in AsO43– adsorption in the Inceptisol amended with aged biochar, whereas a decrease in AsO43– adsorption was observed in the Oxisol amended with aged biochar. Overall, the study has highlighted that adsorption behaviour of aged biochar varies depending on the ion it interacts with, soil properties and solution pH.

Adsorption of cadmium (II) and nickel (II) on dolomite powder

AbstractIn this work, the adsorption behavior of cadmium and nickel was studied using natural dolomite powder. The adsorption experiments were carried out to investigate adsorption parameters including metal ions concentration, solution pH, contact time, and temperature using a batch technique. The equilibrium adsorption isotherm data of the metal ions adsorption were best described by Freundlich, Langmuir, and Dubinin–Radushkevich isotherm models. The adsorption capacity was obtained 1.46 and 1.70 mg/g for cadmium and nickel, respectively. Kinetic studies revealed that the initial uptake was rapid and equilibrium was established in, 120 and 105 min for Cd(II) and Ni(II), respectively. The results showed that the data followed the pseudo-second-order reaction. Thermodynamic analysis showed that the adsorption of the metal ions on dolomite is feasible and exothermic. The mean free energy values obtained using the Dubinin–Radushkevich model for the ions showed that the adsorption of nickel and cadmium ions ...

Analysis of the Adsorption Behaviour of Cadmium on Aluminium-Pillared Diatomite in a Solid/Liquid System Using Classical Adsorption Theory

A readily available effective adsorbent is necessary to adsorb heavy-metal ions from aqueous solutions. In this study, a novel adsorbent with good adsorption properties [Al3+-oligomer-pillared diatomite (Al3+-oligomer-PD)] was prepared and was used to adsorb Cd2+ ions in a solid/liquid system. The property and nature of the Cd2+ ions adsorbed on the surface of the Al3+-oligomer-PD were studied by performing a series of adsorption tests and related surface property analyses. Our study results show that owing to a more favourable pore structure, the PD has a higher adsorption property compared with natural diatomite (ND) and most other common adsorbents. The adsorption capacity of PD is 27.36% greater than ND and also achieves an optimal value of 10.05 mg/l. Certain parameters have a significant effect on Cd2+ ion adsorption. The most suitable isotherm and kinetics models for describing the adsorption of Cd2+ ions are the Freundlich and pseudo-second-order models. The nature of Cd2+ ion adsorption on PD is ...

Adsorption behavior of cadmium onto natural chabazite: batch and column investigations

The objective of the proposed work focused to provide promising solid-phase materials that combine relatively inexpensive and high removal capacity of cadmium ion from aqueous solutions. Four various zeolite minerals including natural clinoptilolite, natural chabazite, natural mordenite, and synthetic mordenite were investigated. The obtained results revealed that natural chabazite has the highest surface area and mesopore volume and appears to be the best adsorbent towards cadmium ion rather than the other investigated zeolite materials. The effective key parameters on the sorption behavior of cadmium on natural chabazite were investigated using batch equilibrium and flow through technique with respect to solution pH, contacting time, adsorbent weight, adsorption isotherm, bed depth, and flow rate. Kinetic curves rather showed a fast adsorption for cadmium, as equilibrium reached within 60 min. The affinity and adsorption capacity of natural chabazite with good fits being obtained using Dubinin–Radushkevich adsorption isotherm giving a maximum capacity of 120 mg/g. Cd+2 and adsorption found to be pH dependent over 2.5–8.5 range; this reveals that the adsorption mechanism may be controlled by chemisorption with the experimental conditions used. The results indicated the feasibility and spontaneous nature of adsorption process at high temperature. Thermodynamic parameter was determined. Column studies showed that cadmium ion removal was a strong function of initial flow rate and bed height. Natural chabazite recommended to be used as reactive barrier for hazardous heavy metals control.

Comparative and competitive adsorption of cadmium, copper, nickel, and lead ions by Iranian natural zeolite

The competitive adsorption behavior of cadmium (Cd2+), copper (Cu2+), nickel (Ni2+), and lead (Pb2+) ions using Iranian natural zeolite has been studied in order to determine its applicability in treating industrial wastewater. Tests to determine both the rate of adsorption and the uptake at equilibrium were performed under batch conditions from single- and multi-component solutions. The optimum conditions for the treatment process were investigated by observing the influence of pH levels, the presence of competing ions, varying the mass of zeolite and different contact time. Adsorption kinetics of the zeolite followed first-order kinetics, showing about 100 % of Pb2+ removal within 40 min and reaching an equilibrium state within 24 h for Cd2+, Cu2+, and Ni2+. The results indicated that removal of metals from single- and multi-component solutions is best described by a Freundlich isotherm, in which the distribution coefficient was in the following order: Pb2+ > Cu2+ > Cd2+ > Ni2+. In the multi-component solutions, metals exhibit competitive adsorption on the zeolite. The adsorption is reduced to 90, 53, 30, and 22 % of single component of Cu2+, Ni2+, Cd2+, and Pb2+, respectively. However, the total adsorption was higher than single component. Finally, soil solution saturation indices and speciation of metals was assessed using Visual MINTEQ 2.6 software, and probability of precipitation of minerals supported by scanning electron microscopy. The research indicates that Cd2+ and Ni2+ retention by zeolite can be viewed as the result of ion exchange reaction, but Pb2+ and Cu2+ retention is both due to ion exchange and precipitation. These results show that Iranian natural zeolite particularly effective in removing cationic heavy metal species from industrial wastewater.

Adsorption behaviour of cadmium by Bacillus cereus M116: some physical and biochemical studies

Adsorption behaviour of cadmium from its aqueous solution by growing and non-growing cells of a mutant strain of Bacillus cereus M116 has been studied to explore the possibility of the biomass to address environmental pollution due to this toxic metal. The results establish that about 75% and 88% of the cadmium can be removed by growing and non-growing cells of the selected strain respectively from its aqueous solution at pH 6.8 ± 0.2, temperature 30 ± 1°C and 120 rpm shaking speed. For growing cells, inoculum size 2% and medium volume 50 mL is found to be optimum. The adsorption rate of cadmium on the biomass is very fast initially and attains equilibrium within 60 min following pseudo second-order rate model (R2 = 0.99). The equilibrium adsorption isotherm can be best described by Langmuir–Freundlich dual model (R2 = 0.99) indicating that both physisorption and chemisorption take place simultaneously. Cadmium can be desorbed from the loaded biomass using mineral acids (0.1 M).

Adsorption behaviour of cadmium on L-methionine immobilized on controlled pore glass

The adsorption behaviour of Cd onto the relative non-polar L-methionine was studied. To this end, L-met was immobilized on controlled pore glass (CPG), incorporated in a microcolumn and inserted in a flow injection system for Cd preconcentration from aqueous solutions. Binding constant of the system was calculated and it turned to be of 1.99, with sites capacity of n = 3.12. The ratio of Cd moles bound to L-met moles was calculated and it was 0.03:1 at pH 9.0. On-line breakthrough curves were used to study the effect of pH, analyte concentration and influent flow rate on Cd retention. A complementary pH study was added with a titration curve. Transient peak areas revealed that Cd stripping from the column occurred instantaneously. The system achieves an enrichment factor of 130, reaching a detection limit of 0.63 ng L − 1 when 10 mL of the solution were passed through the column. The method was successfully applied to Cd determination in the standard reference material (SRM), QC METAL LL2 metals in natural water, as a validation study.

Adsorption of cadmium ion from aqueous solution by ground wheat stems

The adsorption behavior of cadmium on ground wheat stems has been investigated in aqueous solution to understand the physicochemical process involved and to explore the potentiality of wheat stems in wastewater treatment. The results have shown that 0.1032 mmol of cadmium is adsorbed per gram of ground wheat stems. The binding process is strongly affected by solution pH, and the optimum pH is 5.0. The process obeys the Langmuir isotherm model. Blocking of the functional groups on ground wheat stems by chemical modification causes the decrease of the maximum cadmium binding capacity, while increasing the number of the functional groups can enhance the binding capacity of ground wheat stems. Fourier transform infrared spectrometer (FTIR) analysis confirms the chemical modification process and indicates that COO − groups on the ground wheat stems are one of the main active groups in cadmium adsorption process. The X-ray photoelectron spectroscopy (XPS) data further indicates that cadmium is adsorbed as Cd 2+ and is attached to O − groups on the ground wheat stems.

Adsorption Behavior of Cadmium(II) and Lead(II) on Mesoporous Silicate MCM‐41

This investigation examines metal ion adsorption on mesoporous silicate, MCM‐41, synthesized from sodium silicate solution and cethyltrimethylammonium bromide (CTAB). MCM‐41 has potential as an adsorbent material, with a regular hexagonal pore structure, large specific surface area, and large pore volume. The MCM‐41 synthesized for this investigation is characterized using powder X‐ray diffraction and nitrogen adsorption and desorption isotherms data. The adsorption behavior for cadmium(II) and lead(II) onto MCM‐41 was studied by contacting the mesoporous silicate with an aqueous solution of metal salts and acetylacetone. Both Cd2+ and Pb2+ were found to quantitatively adsorb onto MCM‐41. The results of this study suggest that MCM‐41 may have applications in the recovery of toxic metals from waste waters.