Simultaneous Removal Of Cadmium Research Articles

Simultaneous Removal of Cadmium and Disperse Black-9 Dye Using Chemically Modified Rice Husk-Derived Activated Carbon

Heavy metals and organic dyes pose significant environmental concerns due to their persistence, toxicity, and tendency to accumulate in the food chain. These pollutants are often discharged from various industrial sources without proper management, resulting in unacceptable damage to the environment. The use of low-cost agricultural by-products can be a sustainable and green solution for the industrial effluent treatment process. In the present research, the effective removal of Cd2+ and disperse black‒9 (DB‒9) dye simultaneously was planned through the adsorption method utilizing specially activated carbon (AC) derived from rice husk. FTIR, SEM, and XRD were used to characterize the produced AC. The adsorption studies showed that approximately 88% of the dye DB‒9 and 97% of Cd2+ were adsorbed by using optimal dosages of the AC, which were 16 g/L and 12 g/L, respectively. In addition, it was successfully demonstrated that Cd2+ adsorbed AC was capable of binding with DB‒9 and also DB‒9 adsorbed AC is capable of binding with Cd2+. Therefore, a novel strategy for the simultaneous elimination of Cd2+ and DB-9 ideas was successfully implemented in the current study. In addition, equilibrium data were examined to assess the adsorbate-adsorbent system's isotherms. The Langmuir isotherm was determined to be the most well-fitting, with a maximum uptake of 11.48 mg/g. Thermodynamic study (ΔG⁰) showed that the adsorption process was spontaneous, and the adsorption process followed pseudo-second-order kinetics.

Simultaneous extraction of cadmium, nickel, and cobalt ions from acidic aqueous solutions by emulsion liquid membrane using sunflower-kerosene mixture as a diluent; breakage and mass transfer studies

In this study, a simultaneous removal of cadmium, cobalt, and nickel from an aqueous solution through the Green Emulsion Liquid Membrane (GELM) method was carried out. A 7:3 ratio of sunflower oil to kerosene was utilized as the membrane phase stabilized by Span 80 as the emulsifier. D2EHPA as a carrier and HCl as an inner phase were used. Extraction and stripping efficiencies of 97.45% and 98.42% for Cd2+, 96.82% and 97.84% for Co2+, 89.74% and 92.69% for Ni2+, respectively, with the lowest breakage (0.8%) were obtained under the best operating conditions. An extensive investigation of the influence of homogenizer speed, external and internal phase acidity, the HLB value of the surfactant (Tween 80 and Span 80), surfactant and carrier concentrations, volume ratio of the membrane to internal phase, mixer speed, ratio of external to membrane phase emulsification time and extraction time on the stability of membrane, extraction, and stripping efficiencies were carried out. Kinetic analysis of cadmium, cobalt, and nickel extraction was performed using zero, first, and second-order models at optimum conditions. The experimental data fit well with first-order for three metal ions. The coefficient of the total mass transfer (Ft) of cadmium through the GELM technique was 3.28% higher than that of cobalt and 28.61% higher than that of nickel, while the Ft of cobalt is 25.33% higher than that of nickel. Using the recovered membrane, the extraction of the three metal ions for the initial six cycles was extremely efficient under the best conditions.

Simultaneous removal of cadmium(II) and arsenic(III) from aqueous solutions using pyrite-modified biochar: Effects and mechanisms

Simultaneous removal of cadmium [Cd(II)] and arsenic [As(III)] from aqueous systems is still a great challenge. Through mechanical ball milling and thermal activation, pyrite-modified biochar (PMB) was successfully prepared and used to evaluate its synchronous removal effect and mechanism of Cd(II) and As(III) from aqueous solutions. PMB exhibited a maximum adsorption capacity of 51.0 mg·g−1 for Cd(II) (pH=6) and 65.9 mg·g−1 for As(III) (pH=4) at 25 °C, surpassing that of biochar by 1.5 and 5.7 times, respectively. Interestingly, in the mixed Cd-As system, the presence of Cd(II) hindered the adsorption of As(III) onto PMB, while the presence of As(III) enhanced the adsorption of Cd(II). Additionally, the removal of Cd(II) and As(III) by PMB remained in the range of 70%− 80% under the competition of cations (K+, Mg2+) and anions (NO3-, SO42-), except for the severe inhibition of Cd(II) and As(III) removal by Ca2+ and PO43- due to their specific physicochemical properties. The adsorption of Cd(II) by PMB followed the Langmuir and pseudo-second-order models, involving ion exchange (formation of CdS) and complexation as the main removal mechanisms. And the adsorption of As(III) followed the Freundlich and pseudo-second-order models, involving oxidation of As(III) to arsenic(V) and further complexation as the primary removal mechanisms. After four adsorption-desorption cycles, the adsorption performance of PMB for Cd(II) and As(III) could still reach 78% and 68% of the initial performance. Overall, the results demonstrated that PMB was the preferred eco-friendly material for efficiently removing Cd(II) and As(III) from co-pollution aqueous solutions.

The simultaneous removal of cadmium (II) and lead (II) from wastewater with the application of green synthesized magnesium silicate hydrate

To the purpose of solving the problems of coal-gangue accumulation in the mine and pollution of cadmium (II) and lead (II) in wastewater, magnesium silicate hydrate (M-S-H) was synthesized from coal-gangue by thermochemical. M-S-H had removed Cd(II) and Pb(II) by adsorption. The characterization of M-S-H and adsorption effects factors, including initial solution pH, initial metal concentration, adsorbent dose, temperature, reaction time, and coexisting ions were explored for adsorption performance. The solution pH was precisely controlled by a pH meter. The adsorption temperature was controlled by a thermostatic gas bath oscillator with an error of ±0.3. These results from this study revealed that M-S-H surface area increased from 8.12 to 26.15 m2/g with a pore volume of 0.12 cm3/g. The maximum adsorptions of Cd(II) and Pb(II) by M-S-H were 59.52 and 83.33 mg g−1, respectively. The adsorption performance for Cd(II) and Pb(II) reached saturation at pH 5, temperature 25°C, M-S-H 6 g/L, reaction time 90 min, and metal concentration 300 mg/L. Cd(II) and Pb(II) adsorption were spontaneous and endothermic and well fitted with the pseudo-second-order kinetic and Langmuir isotherm adsorption models. The adsorption mechanisms were electrostatic interaction, ion exchange, and surface complexation. This research indicated that the synthesized M-S-H from coal gangue was efficiently eliminated metal ions from water, opening up new possibilities for coal gangue reuse.

Simultaneous removal of cadmium, lead, chromate by biochar modified with layered double hydroxide with sulfide intercalation

In this study, a novel KOH-activated biochar modified with Mg2Al-LDH with S2− intercalation (KBC-LDH-S) was proposed for simultaneous adsorption of anions and cations. The adsorption capacity, thermodynamic and kinetic studies, effects of initial temperature and solution pH were investigated. Furthermore, the adsorption characteristics in both single and ternary Pb-Cd-Cr systems were investigated. Comparing with bare biochar, the adsorption capacity of KBC-LDH-S was increased by 387.8 % for Cd2+ (190.4 mg/g), 358.1 % for Pb2+ (392.2 mg/g), 1106.0 % for total Cr (170.7 mg/g) and 4602 % for Cr6+ (833.8 mg/g). The S2− intercalation effectively increased the adsorption capacity of CrO42− by 3370 % and promoted simultaneous adsorption. The interlayer anion exchange and redox reaction occurred between CrO42− and S2− to generate Cr3+, and then promoted the adsorption of CrO42−. Besides, the adsorption amount and total removal efficiency first increased and then decreased with the increasing concentration in the Pb-Cd-Cr ternary system.

Simultaneous removal of cadmium and lead by biochar modified with layered double hydroxide

Biochar has great potential in remediation of heavy metal pollution due to the various surface heteroatomic groups and porous properties, while the conventional pyrolytic carbonization process cannot provide enough oxygen-containing functional groups for the removal efficiency and stability in the industrial application. In this study, a facile and green method to synthesize the novel biochar modified with layered double hydroxide (LDH) to enhance the heavy metal removal. The effect of LDH modification on biochar, adsorption characteristics and simultaneous adsorption mechanisms in PbCd binary system were investigated. The LDH modification would activate biochar and avoid hydrotalcite agglomeration. Comparing with bare biochar, the adsorption capacity of LDH modified biochar (KBC-LDH) was increased by 307.8% for Cd2+ (181.53 mg/g) and 254.5% for Pb2+ (368.75 mg/g). Besides, the adsorption amount and total removal efficiency first increased and then decreased with the increasing concentration of the mixed contaminants in the PbCd binary system. The addition of Pb2+ or Cd2+ with low concentration could effectively promote the adsorption capacity of another ion in the PbCd binary system, but inhibited adsorption with the further increase of the contaminant concentration. Furthermore, the repeatability and stability of KBC-LDH increased by 149.1% and 51.2% compared with bare biochar, respectively.

Simultaneous removal of cadmium and lead ions from aqueous solutions by nickel oxide-decorated reduced graphene oxides

Simultaneous removal of cadmium and lead ions from aqueous solutions by nickel oxide-decorated reduced graphene oxides

Simultaneous Removal of Cadmium and Copper from a Binary Solution by Cathodic Deposition Using a Spiral-Wound Woven Wire Meshes Packed Bed Rotating Cylinder Electrode

Simultaneous Removal of Cadmium and Copper from a Binary Solution by Cathodic Deposition Using a Spiral-Wound Woven Wire Meshes Packed Bed Rotating Cylinder Electrode

Simultaneous removal of cadmium, zinc and manganese using electrocoagulation: Influence of operating parameters and electrolyte nature

In the present study, the influence of operating parameters and electrolyte nature on the simultaneous removal of toxic metals (cadmium, zinc and manganese) from synthetic smelting wastewater by batch electrocoagulation was investigated. This wastewater contained high concentrations of anion–cation electrolytes. Results indicated that the efficiency of heavy metals removal can be enhanced by increasing the solution pH and current density. The Fe–Fe electrode combination is more effective than the other combinations (Al–Al, Al–Fe and Fe–Al). The interaction of heavy metal ions showed that the increase of initial Zn2+ concentration adversely affects on Cd2+ removal. In addition, the single chloride system exhibits the optimum removal efficiency on Mn2+. Single sulfate and binary anion systems exert a more positive effect on Cd2+ and Zn2+ removal because of the stronger charge neutralization and destabilization of iron hydroxide flocs. Increases of Ca2+ and Mg2+ ions exert a significant negative effect on metal removal. However, the addition of a small amount of sodium chloride into a high sulfate and hardness solution can accelerate the removal of heavy metals. Finally, the sludge samples generated from electrocoagulation were characterized by XRD and SEM–EDS analyses.

Simultaneous removal of cadmium and nitrate in aqueous media by nanoscale zerovalent iron (nZVI) and Au doped nZVI particles

Nanoscale zerovalent iron (nZVI) has demonstrated high efficacy for treating nitrate or cadmium (Cd) contamination, but its efficiency for simultaneous removal of nitrate and Cd has not been investigated. This study evaluated the reactivity of nZVI to the co-contaminants and by-product formation, employed different catalysts to reduce nitrite yield from nitrate, and examined the transformation of nZVI after reaction. Nitrate reduction resulted in high solution pH, negatively charged surface of nZVI, formation of Fe3O4 (a stable transformation of nZVI), and no release of ionic iron. Increased pH and negative charge contributed to significant increase in Cd(II) removal capacity (from 40 mg/g to 188 mg/g) with nitrate present. In addition, nitrate reduction by nZVI could be catalyzed by Cd(II): while 30% of nitrate was reduced by nZVI within 2 h in the absence of Cd(II), complete nitrate reduction was observed in the presence of 40 mg-Cd/L due to the formation of Cd islands (Cd(0) and CdO) on the nZVI particles. While nitrate was reduced mostly to ammonium when Cd(II) was not present or at Cd(II) concentrations ≥ 40 mg/L, up to 20% of the initial nitrate was reduced to nitrite at Cd(II) concentrations < 40 mg/L. Among nZVI particles doped with 1 wt. % Cu, Ag, or Au, nZVI deposited with 1 wt. % Au reduced nitrite yield to less than 3% of the initial nitrate, while maintaining a high Cd(II) removal capacity.

Simultaneous removal of cadmium and sulfamethoxazole from aqueous solution by rice straw biochar

The simultaneous sorption behavior and characteristics of cadmium (Cd) and sulfamethoxazole (SMX) on rice straw biochar were investigated. Isotherms of Cd and SMX were well modeled by the Langmuir equation (R(2)>0.95). The calculated maximum adsorption parameter (Q) of Cd was similar in single and binary systems (34129.69 and 35919.54 mg/kg, respectively). However, the Q of SMX in a binary system (9182.74 mg/kg) was much higher than that in a single system (1827.82 mg/kg). The presence of Cd significantly promoted the sorption of SMX on rice straw biochar. When the pH ranged from 3 to 7.5, the sorption of Cd had the characteristics of a parabola pattern with maximum adsorption at pH 5, while the adsorption quantity of SMX decreased with increasing pH, with maximum adsorption at pH 3. The amount of SMX adsorbed on biochar was positively correlated with the surface area of the biochar, and the maximum adsorption occurred with d 250 biochar (biochar with a diameter of 150-250 μm). Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) showed that the removal of Cd and SMX by rice straw biochar may be attributed to precipitation and the formation of surface complexes between Cd or SMX and carboxyl or hydroxyl groups. The results of this study indicate that rice straw biochar has the potential for simultaneous removal of Cd and SMX from co-contaminated water.

Simultaneous removal of cadmium from kaolin and catholyte during soil electrokinetic remediation

The influence of the pH variation of a catholyte on the removal of Cd from kaolin and the subsequent precipitation of the Cd in the catholyte was evaluated during soil electrokinetic remediation (EKR). The pH variations of the catholyte were induced by the injection of nitric acid (HNO3) at different concentrations (0.00, 0.01, 0.06, 0.12, 0.18, 0.24, 0.42M) at a constant rate (0.6ml/h). The addition of the acid enhanced the removal of Cd from kaolin. When the concentration of the injected HNO3 was higher than 0.06M, both the electrical energy and acid consumption increased. When the concentration of the injected acid was higher than 0.12M, the pH in the catholyte markedly increased. The best results were obtained by using 0.06M HNO3. At this concentration, it was possible to extract 98% of the Cd from kaolin, of which 63% precipitated in the catholyte. Thirteen liters of HNO3 and 30kW-h of electrical energy were required per cubic meter of treated kaolin. The average extraction rate of Cd was extracted from kaolin reached high values (0.38mg/h) when less than 90% of the Cd had been removed. For the remaining 10%, the extraction rates noticeably decreased (0.025–0.059mg/h).

Simultaneous phenanthrene and cadmium removal from contaminated soil by a ligand/biosurfactant solution

Surfactants and inorganic ligands are pointed as efficient to simultaneous removal of heavy metals and hydrophobic organic pollutants from soil. However, the biosurfactants are potentially less toxic to soil organisms than other chemical agents. Thus, in this study the efficiency of combinations of iodide (I(-)) ligand and surfactants produced by different bacterial species in the simultaneous removal of cadmium (Cd(2+)) and phenanthrene in a Haplustox soil sample was investigated. Four microbial surfactants and the synthetic surfactant Triton X-100 were tested with different concentrations of ligand. Soil samples contaminated with Cd(2+) and phenanthrene underwent consecutive washings with a surfactant/ligand solution. The removal of Cd(2+) increased with increased ligand concentration, particularly in solutions containing biosurfactants produced by the bacterial strains Bacillus subtilis LBBMA155 (lipopeptide) and Flavobacterium sp. LBBMA168 (mixture of flavolipids) and Triton X-100. Maximum Cd(2+) removal efficiency was 99.2% for biosurfactant produced by Arthrobacter oxydans LBBMA 201 (lipopeptide) and 99.2% for biosurfactant produced by Bacillus sp. LBBMA111A (mixed lipopeptide) in the presence of 0.336mol iodide l(-1), while the maximum efficiency of Triton X-100 removal was 65.0%. The biosurfactant solutions removed from 80 to 88.0% of phenanthrene in soil, and the removal was not influenced by the presence of the ligand. Triton X-100 removed from 73 to 88% of the phenanthrene and, differently from the biosurfactants, iodide influenced the removal efficiency. The results indicate that the use of a single washing agent, called surfactant-ligand, affords simultaneous removal of organic contaminants and heavy metals.

Simultaneous removal of cadmium and turbidity in contaminated soil-washing water by DAF and electroflotation

The removal of cadmium and turbidity from contaminated soil-washing water was studied by dissolved air flotation (DAF) and electroflotation at laboratory scale by using sodium lauryl sulfate (SLS) as an anionic surfactant, and calcium hydroxide (Ca(OH)2) as a coagulant. Using DAF, and in the presence of SLS or Ca(OH)2, the maximum recovery rate of cadmium obtained at a stoichiometric cadmium to collector and coagulant ratio of 1:4.5 was 51.1% and 80.8%, while the removal rate of turbidity was 18.4% and 19.2%. However, satisfactory cadmium and turbidity removal was not obtained by DAF. Much more significant removal of cadmium (100%, not detected in the residual) and turbidity (95.7%) was obtained by electroflotation using an aluminium metal plate as electrode, which generated hydroxide and aluminum ion. As a consequence, electroflotation is considered an effective method to separate cadmium and turbidity from contaminated soil-washing water. The electroflotation process may have practical applications for the removal of other hazardous metals from contaminated soil-washing water.