Removal of lead using alginate–eggshell composite beads as a low-cost adsorbent and application for battery manufacturing effluent

Efficient removal of hazardous lead, cadmium, and arsenic from aqueous environment by iron oxide modified clay-activated carbon composite beads

The present article explores the ability of five different combinations of two adsorbents (Arachis hypogea shell powder and Eucalyptus cameldulensis saw dust) to remove Pb(II) from synthetic and lead acid batteries wastewater through batch and column mode. The effects of solution pH, adsorbent dose, initial Pb(II) concentration and contact time were investigated with synthetic solutions in batch mode. The Fourier transform infrared spectroscopy study revealed that carboxyl and hydroxyl functional groups were mostly responsible for the removal of Pb(II) ions from test solutions. The kinetic data were found to follow pseudo-second-order model with correlation coefficient of 0.99. Among Freundlich and Langmuir adsorption models, the Langmuir model provided the best fit to the equilibrium data with maximum adsorption capacity of 270.2 mg g−1. Column studies were carried out using lead battery wastewater at different flow rates and bed depths. Two kinetic models, viz. Thomas and Bed depth service time model, were applied to predict the breakthrough curves and breakthrough service time. The Pb(II) uptake capacity (q e = 540.41 mg g−1) was obtained using bed depth of 35 cm and a flow rate of 1.0 mL min−1 at 6.0 pH. The results from this study showed that adsorption capacity of agricultural residues in different combinations is much better than reported by other authors, authenticating that the prepared biosorbents have potential in remediation of Pb-contaminated waters.

The aim of this study is to explore naturally occurring sorbents that have high affinity for heavy metal treatment. In this respect, series of polymer‐clay composite beads that consists of Na‐alginate and montmorillonite clay were prepared using CaCl2 as crosslinker. The prepared composite bead was characterized by scanning electron microscope (SEM). Removal of lead from aqueous solution using this bead was then studied in batch adsorption experiments. The amount of lead removed was found to increase as the percent of Na‐alginate increase in the composite beads. The experimental results also showed that the equilibrium contact time was obtained within ∼ 100 min with (t1/2) of 50% adsorption in less than 10 min. Lead adsorption was found to be strongly pH‐dependent and display a maximum uptake capacity (244.6 mg/g) at pH 6 and minimum uptake (76.6 mg/g) at pH 1. Maximum lead adsorption was found to increase with increasing initial lead concentration in the feed solution and with decreasing temperature of experiment. Based on alginate‐montmorillonite beads packed columns, a highly efficient method for Pb(II) removal from aqueous solution was developed. The effect of flow rate on adsorption of 100 mg/L Pb(II) in the packed‐bed column was investigated by changing the flow rate between 0.5 and 2.5 mL min−1. The recovery of 100 mg/L Pb(II) in the packed‐bed column was found to be 100% at flow rates 0.5 and 1 mL min−1 then lowered to be 93% and 84% at flow rates 1.5 and 2.5 mL min−1, respectively. The effect of Pb(II) flow concentration ranging from 10 to 1000 mg/L on the adsorption of lead ions at constant flow rate 1.0 mL min−1 was also studied using column procedure. Technical feasibility for the uses of the prepared composite beads for the treatment of actual polluted wastewater samples collected from some industrial cities in Egypt was investigated. The evaluation of the system was performed by a complete analysis of heavy metals in the wastewater samples before and after the treatment process. The results showed a promising possibility for producing wastewater of better quality using such prepared beads. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

The aim of present study was to investigate the removal of lead and copper from textile wastewater using waste egg shells in a continuous stirred tank reactor. The effect of initial pH, metal concentration, adsorbent dosage and retention time were investigated. Optimum adsorption of lead (80%) was obtained at pH 6, initial metal concentration 20 mg/L, adsorbent dosage 12.5 g/L and retention time 90 minute. Also, optimum adsorption of copper (71%) was obtained at pH 6, initial metal concentration 15 mg/L, adsorbent dosage 15 g/L and retention time 75 minute. Langmuirs, Freundlich and Temkin isotherms were used for the mathematical description of adsorption equilibrium. Langmuir isotherm showed the best fitting to the isotherm equilibrium data, with a maximum adsorption capacity (qm) of 4.33 mg/g and 3.54 mg/g for lead and copper, respectively. Results revealed that pseudo-second order adsorption kinetic equation fit the data with a high correlation coefficient (R2 more than 0.97). Based on the results of the present study, egg shells is suitable to be used for the removal of lead and copper from textile wastewater.

Korean pressurized water reactors (PWRs) generally use radioactive effluent monitors for monitoring the concentration of radioactive effluents released to the environment. In this study, the operating margins for radioactive effluent monitors were analyzed to determine the levels of real-time concentration of effluents compared to effluent control limits (ECLs), the regulatory limits. The results show that the concentration of radioactive effluents released from Korean PWRs complied with the ECLs during the years 2012–2016. It was also found that outages at Korean PWRs did not impact the operating margins for radioactive effluent monitors; that is, there was no remarkable difference of the concentration of effluents between normal operation and maintenance periods. In terms of simultaneous effluent releases, the results demonstrate that exceeding the ECLs is unlikely to occur even under the hypothetical condition of coincident effluent releases from multiple discharge points at a Korean PWR.

Structural evolution of chitosan–palygorskite composites and removal of aqueous lead by composite beads

Composites of sodium alginate based - Functional materials towards sustainable adsorption of benzene phenol derivatives - Bisphenol A/Triclosan

Removal of lead(II) from aqueous solutions using carbonate hydroxyapatite extracted from eggshell waste

In this research, the removal of lead from the aqueous solution was investigated using natural nontoxic zeolite (clinoptilolite) as a low-cost adsorbent in order to reduce human exposure to it. The clinoptilolite zeolite obtained from the Semnan area was characterized by X-ray diffraction pattern, FTIR spectroscopy and scanning electron microscopy (SEM). The central composite design (CCD) defined under the response surface methodology (RSM) was used for designing the experiments and analyzing the sorption of lead. Three parameters of contact time (43.07-101.93 min), initial concentration (508-3006 mg/L) and temperature (20-51˚C) were applied to optimize the removal percentage of lead by zeolite. It was found that the initial concentration is the most important parameter affecting the removal percentage of lead, followed by the temperature of process. The optimum values of initial concentration, contact time and temperature were found to be 2750 ppm, 82.87 min and 65°C for 99.81% removal of lead, respectively, with a high desirability of 0.990. The adsorption data fitted the Freundlich adsorption model better than the Langmuir model, with the maximum sorption capacity of the clinoptilolite zeolite for Pb(II) equaling 136.99 (mg/g).

Removal of lead and zinc ions from water by low cost adsorbents

The sorption behavior of lead ions on coconut coir has been investigated to decontaminate lead ions from aqueous solutions. Various physico-chemical parameters were optimized to simulate the best conditions in which this material can be used as an adsorbent. Maximum adsorption was observed at 0.0001 to 0.001 mol L−1 of acid solutions (HNO3, HCl and HClO4) using 0.4 g of adsorbent for 4.83 × 10−5 mol L−1 lead concentration in ten minutes equilibration time. The adsorption of lead was decreased with the increase in the concentrations of all the acids used. The kinetic data indicated an intraparticle diffusion process with sorption being pseudo-second order. The determined rate constant k2 was 8.8912 g mg−1 min−1. The adsorption data obeyed the Freundlich isotherm over the lead concentration range of 2.41 × 10−4 to 1.45 × 10−3 mol L−1. The characteristic Freundlich constants i.e., 1/n = 0.44 ± 0.02 and K = 0.184 ± 0.0096 m mol g−1 have been computed for the sorption system. The sorption mean free energy from the Dubinin-Radushkevich isotherm is 10.48 ± 0.72 kJ mol−1 indicating the ion-exchange mechanism of chemisorption. The uptake of lead increases with the rise in temperature (293–333 K). Thermodynamic quantities i.e., ΔG, ΔS, and ΔH have also been calculated for the system. The sorption process was found to be endothermic. The proposed procedure was successfully applied for the removal of lead from battery wastewater samples.

Removal of lead from aqueous solutions using Cassia grandis seed gum-graft-poly(methylmethacrylate)

In this study, the pyrolysis of sewage sludge was employed to prepare a biochar (BC) adsorbent that was modified using eggshell wastes, obtaining eggshell-modified biochar (EMBC). The adsorbent material was used for the removal of monoethylene glycol (MEG) from aqueous solutions under various adsorption conditions. Results showed that the specific surface area of EMBC (i.e., 3.95 m2/g) was approximately twofold higher than that of BC, implying that the application of eggshell waste would improve the surface adsorption performance. The optimum adsorption pH value was 7, achieving MEG removal efficiencies of 29.9% for BC and 89.9% for EMBC using adsorbent dosage = 2 g/L, initial MEG concentration = 100 mg/L, and 25 °C within 60 min. The adsorption mechanisms were illustrated regarding XRD, FTIR, and SEM, demonstrating that surface adsorption, pore-filling, precipitation, and complexation contributed to the adsorption process. The adsorption data fitted well to the Langmuir isotherm model with the maximum monolayer adsorption capacity of 12.20 mg/g, implying a reversible physisorption mechanism. Based on a techno-economic feasibility assessment, the preparation of BC and EMBC adsorbents for the treatment of 1 m3 of wastewater-containing ethylene glycol would require capital costs of 4.80 and 6.50 US$, respectively. The selling of adsorbents and the economic benefit of tertiary treated water showed adequate annual profitability with payback periods of 12.97 and 6.79 years for the BC and EMBC scenarios, respectively. Hence, the study succeeded in preparing efficient and low-cost adsorbents that could be used for the tertiary treatment of petrochemical industrial wastewater containing toxic environmental pollutants.

Tartrazine yellow is a dye commonly used in the food, textile, cosmetic and pharmaceutical industries. The effluents generated containing this contaminant must be treated since it presents potential carcinogenicity to the cells. The adsorption stands out among the other techniques used to remove dye from wastewater due to its ease of operation and implementation, and high removal rate. However, the production of effective and low-cost adsorbents is a constant challenge. Gelatin is a promising compound for the production of adsorbent composites, enabling the improvement of its low mechanical properties and accelerated degradation, by the addition of carbonaceous, such as carbon nanotubes (CNT’s). Taking into account economic and environmental aspects, gelatin can be recovered from chromium-tanned leather wastes (RCTLW). Thus, this work aimed to study the adsorption of the tartrazine yellow dye by adsorbent composites based on: (1) commercial gelatin/CNT’s beads and (2) RCTLW gelatin/CNT’s beads. Commercial and RCTLW gelatin composite beads showed an adsorption capacity of 202.39 and 131.32 mg.g–1, respectively, estimated by the Langmuir model. In adsorption kinetics, the density continued to increase after 300 min for both the composite materials, with better prediction of the pseudo-first order model. In the reuse study, the commercial and RCTLW gelatin composite beads proved to be usable for up to 10 cycles, with regenerations of 45 to 68% and 45 to 61%, respectively. In general, the composite beads of gelatin showed promise for the adsorption of dyes, mainly RCTLW gelatin, since it makes possible the use and minimization of wastes.

Background: Removal of lead (II) ions from supply water using an inexpensive adsorbent is essential. It is recommended that low-cost adsorbents are developed to effectively remove lead (II) ions from aqueous solutions. The aim of the study is to develop and validate models for predicting the performance of carboxylated jute stick derived activated carbon (JSAC-COOH) in removing lead (II) ions from aqueous solution, which can assist the water supply authorities in supplying lead (II) free drinking water to the communities at a low-cost. Methods: Controlled laboratory experiments were conducted following the statistical “Design of Experiments” through varying the factors affecting the performance of JSAC-COOH in removing lead (II) ions. The performance of JSACCOOH was investigated for different concentrations of lead (II) ions (range: 50 - 500 mg/L) at variable experimental conditions (temperature: 15°C and 27°C; pH: 4.0 and 7.0) and time (1, 10, 30 and 60 min). Several models (Linear and non-linear) were investigated and validated for predicting the concentrations of lead (II) ions in aqueous solution. Results: The prepared JSAC-COOH had a surface area of 615.3 m2 /g. In 60 min, up to 99.8% removal of lead (II) ions was achieved. Few models showed very good to excellent predictive capabilities with coefficients of determination in the range of 0.85–0.95. The model validation experiments showed the correlation coefficients in the range of 0.84 – 0.98. Conclusion: The models have the capabilities to reasonably predict the final concentrations of lead (II) ions, which can be used in controlling the effluent lead (II) ion concentrations. The proposed adsorbent is likely to be low-cost as it was developed using the commonly available agricultural byproduct.