Heavy Metals Removal from Wastewater by Using Activated Peat

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2309-2312 ◽  
Author(s):  
J. S. D'Avila ◽  
C. M. Matos ◽  
M. R. Cavalcanti
Keyword(s):  
Heavy Metals ◽  
Cation Exchange ◽  
Metal Ion ◽  
Fixed Bed ◽  
Exchange Capacity ◽  
Ion Concentration ◽  
Fixed Bed Reactor ◽  
Stirred Tank Reactors ◽  
Metals Removal ◽  
Low Efficiency

The processes used to remove heavy metals from inorganic wastewater have in general low efficiency. The use of activated peat obtained by using a process similar to a cation exchange reaction increases the removal efficiency up to five times when compared with peat “in natura”. The main objective of this work is to show the fundamental mathematical model, governed by diffusion process and the algorithms utilized to design the batch and the continuous feed stirred tank reactors or in some cases a fixed bed reactor. The principal dimensions of these equipments are obtained from the knowledge of the activated peat's cation exchange capacity used in the process, and the main chemical characteristics of the heavy metal ion contained in the wastewater. Besides, two important parameters are also included: the ion concentration and the efficiency of the process obtained from laboratory kinetics experiments. For example Pb+2 is removed l:rom a wastewater at a concentration of 50g/m3 in five minutes or less, with an efficiency of 98%.

Mercury Sorption on Chitosan

2007 ◽  
Vol 20-21 ◽  
pp. 635-638 ◽  
Author(s):  
Karol Campos ◽  
Eric Guibal ◽  
Francisco Peirano ◽  
M. Ly ◽  
Holger Maldonado
Keyword(s):  
Particle Size ◽  
Metal Ion ◽  
Fixed Bed ◽  
Sorption Isotherms ◽  
Sorption Kinetics ◽  
Breakthrough Curves ◽  
Ion Concentration ◽  
Fixed Bed Reactor ◽  
Continuous Systems ◽  
Maximum Sorption

Mercury sorption on chitosan was investigated in batch and continuous systems. Chitosan sorption properties were determined through sorption isotherms. Langmuir and Freundlich equations were used for the modeling of isotherms at pH 5. In batch systems, maximum sorption capacities reached 550 mg Hg/g. Sorption kinetics have been studied as a function of sorbent particle size and stirring rate. Dynamic removal of mercury was tested in a fixed bed reactor investigating the following parameters: particle size, column size, flow velocity and metal ion concentration. Clark and Adams-Bohart models were evaluated for the simulation of breakthrough curves. This study shows that chitosan is an effective sorbent for the treatment and recovery of mercury from dilute effluents at near neutral pH.

Effects of high pH solutions with large monovalent cation concentrations on cation exchange properties

Soil Research ◽  
1996 ◽  
Vol 34 (2) ◽  
pp. 229 ◽  
Author(s):  
RE Liefering ◽  
CDA Mclay
Keyword(s):  
Organic Matter ◽  
Cation Exchange ◽  
Negative Charge ◽  
Monovalent Cation ◽  
Exchange Capacity ◽  
Exchangeable Cations ◽  
Ion Concentration ◽  
Exchangeable Sodium ◽  
High Ph ◽  
Exchange Properties

Disposal of strongly alkaline industrial liquid wastes, which contain large monovalent cation concentrations, by means of land treatment systems is becoming increasingly common. This study investigated the effects of solutions with large monovalent cation concentrations and high pH on cation exchange properties in four New Zealand soils with different clay mineralogies. The soils were shaken with a range of concentrations (0–0.3 M) of NaOH, KOH, NaCl, and KCl. Cation exchange capacity (CEC) and exchangeable cations (Ca2+, Mg2+, K+, and Na+) were measured following shaking and washing procedures. Although the hydroxide solutions dissolved significant amounts of organic matter from all soils, there was still a net increase in CEC measured at all hydroxide concentrations. The magnitude of the CEC increase was dependent on hydroxide concentration. The increase in CEC is attributed to newly generated negative charge on surfaces which possess variable charge (i.e. pH dependent) characteristics such as edge sites of clay minerals, sesquioxides, and the undissolved organic matter remaining in the soil. In contrast to hydroxide solutions, no increase in CEC was measured in chloride-treated samples. Increases in the concentration of all treatment solutions resulted in increases in the exchangeable ion concentration of the index cation used in the treatment solution (either Na+ or K+) and decreases in concentration of the other three exchangeable cations. In general, higher exchangeable sodium percentage (ESP) values were measured in samples treated with NaOH than samples treated with NaCl at all concentrations. Similarly, higher exchangeable potassium percentage (EPP) was measured in samples treated with KOH than samples treated with KCl at all concentrations. The higher ESP and EPP values recorded when hydroxide solutions were used as treatments are attributed to the newly generated negative charges being counter-balanced by the monovalent index cation present in the treatment solution. It is suggested that existing equations commonly used to predict ESP and EPP values are unsuccessful for accurately predicting changes when soils are treated with hydroxide solutions, due to their inability to account for the newly generated exchange sites. The equations did, however, adequately predict the effects of both chloride solutions on ESP and EPP.

scholarly journals Effective Heavy Metals Removal from Water Using Nanomaterials: A Review

Processes ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 645 ◽  
Author(s):  
Mohamed A. Tahoon ◽  
Saifeldin M. Siddeeg ◽  
Norah Salem Alsaiari ◽  
Wissem Mnif ◽  
Faouzi Ben Rebah
Keyword(s):  
Heavy Metals ◽  
Cost Effective ◽  
Ion Concentration ◽  
Wastewater Remediation ◽  
Toxic Heavy Metals ◽  
Surrounding Environment ◽  
Metals Removal ◽  
Physicochemical Factors ◽  
Magnetic Metal ◽  
High Threat

The discharge of toxic heavy metals including zinc (Zn), nickel (Ni), lead (Pb), copper (Cu), chromium (Cr), and cadmium (Cd) in water above the permissible limits causes high threat to the surrounding environment. Because of their toxicity, heavy metals greatly affect the human health and the environment. Recently, better remediation techniques were offered using the nanotechnology and nanomaterials. The attentions were directed toward cost-effective and new fabricated nanomaterials for the application in water/wastewater remediation, such as zeolite, carbonaceous, polymer based, chitosan, ferrite, magnetic, metal oxide, bimetallic, metallic, etc. This review focused on the synthesis and capacity of various nanoadsorbent materials for the elimination of different toxic ions, with discussion of the effect of their functionalization on the adsorption capacity and separation process. Additionally, the effect of various experimental physicochemical factors on heavy metals adsorption, such as ionic strength, initial ion concentration, temperature, contact time, adsorbent dose, and pH was discussed.

scholarly journals Cu adsorption in fixed bed column with three different influent concentration

2019 ◽  
Vol 120 ◽  
pp. 03003
Author(s):  
Huang-Mu Lo ◽  
Kae-Long Lin ◽  
Min-Hsin Liu ◽  
Hsung-Ying Chiu ◽  
Fang-Cheng Lo
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Activated Carbon ◽  
Fixed Bed ◽  
Thomas Model ◽  
Fixed Bed Column ◽  
Nelson Model ◽  
Influent Concentration ◽  
Carbon Adsorption ◽  
Metals Removal

Heavy metals from the electroplating wastewater might cause environmental pollution if not well treated. Generally, carbon adsorption might be used for the final step for further trace metals removal. This study investigated the heavy metal Cu adsorption in the fixed bed column with 1, 10 and 100 mg/L influent concentration. Results showed that KAB decreased as influent Cu concentration increased from 1 to 100 mg/L while N0 increased as influent concentration increased from 1 to 100 mg/L as can be found in Adams-Bohart model. R2 was found between 0.8579 and 0.9182. In Thomas model. KTH and q0 showed the similar trend as KAB and N0 in the Adams-Bohart model. KTH decreased as influent Cu concentration increased from 1 to 100 mg/L. q0 increased as influent Cu concentration increased from 1 to 100 mg/L. R2 of regression model was found between 0.9065 and 0.9836. In Yoon-Nelson model. KYN increased as influent Cu concentration increased from 1 to 100 mg/L while τ decreased as influent Cu concentration increased from 1 to 100 mg/L. Results showed that the three models of Adams-Bohart model, Thmoas model and The Yoon-Nelson model were suitable for the description of Cu adsorption by activated carbon.

Treatment of metals-contaminated wastewaters by use of natural zeolites

1999 ◽  
Vol 39 (10-11) ◽  
pp. 115-122 ◽  
Author(s):  
S. K. Ouki ◽  
M. Kavannagh
Keyword(s):  
Heavy Metals ◽  
Metal Removal ◽  
Low Cost ◽  
Exchange Capacity ◽  
Natural Zeolites ◽  
Al Substitution ◽  
Metals Removal ◽  
Exchange Material ◽  
Na Ions ◽  
Competing Ions

This paper assesses the potential of natural zeolite utilization as a low-cost in exchange material for heavy metals removal. Two natural zeolites, clinoptilolite and chabazite, have been evaluated with respect to their selectivity and removal performance for the treatment of effluents contaminated with mixed heavy metals (Pb, Cd, Cu, Zn, Cr, Ni and Co). The effects of relevant parameters such as chemical treatment, metals concentration, pH, and presence of competing ions were examined. The results showed that the received zeolites contained exchangeable K, Ca and Na ions, but exposing them to concentrated NaCl solutions converted them to a homoionic state in the Na form which improved their exchange capacity. Clinoptilolite and chabazite exhibited different selectivity profiles for all metals studied except for Pb for which both zeolites performed exceptionally well. The results also showed that chabazite exchange capacity is superior to that of clinoptilolite mainly due to the higher Al substitution of Si which provides chabazite with a negative framework favourable to higher exchange capability. The pH was found to have an effect on metal removal as it can influence both the character of the exchanging ions and the zeolite itself. Overall, the removal mechanism was controlled by ion exchange and precipitation was proven negligible.

Adsorption of heavy metals from aqueous solutions by Mg–Al–Zn mingled oxides adsorbent

2016 ◽  
Vol 74 (7) ◽  
pp. 1644-1657 ◽  
Author(s):  
Mona El-Sayed ◽  
Gh. Eshaq ◽  
A. E. ElMetwally
Keyword(s):  
Heavy Metals ◽  
Metal Ion ◽  
Second Order ◽  
Ion Concentration ◽  
Precipitation Method ◽  
Isotherm Models ◽  
Infrared Spectrometry ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Pseudo Second Order

In our study, Mg–Al–Zn mingled oxides were prepared by the co-precipitation method. The structure, composition, morphology and thermal stability of the synthesized Mg–Al–Zn mingled oxides were analyzed by powder X-ray diffraction, Fourier transform infrared spectrometry, N2 physisorption, scanning electron microscopy, differential scanning calorimetry and thermogravimetry. Batch experiments were performed to study the adsorption behavior of cobalt(II) and nickel(II) as a function of pH, contact time, initial metal ion concentration, and adsorbent dose. The maximum adsorption capacity of Mg–Al–Zn mingled oxides for cobalt and nickel metal ions was 116.7 mg g−1, and 70.4 mg g−1, respectively. The experimental data were analyzed using pseudo-first- and pseudo-second-order kinetic models in linear and nonlinear regression analysis. The kinetic studies showed that the adsorption process could be described by the pseudo-second-order kinetic model. Experimental equilibrium data were well represented by Langmuir and Freundlich isotherm models. Also, the maximum monolayer capacity, qmax, obtained was 113.8 mg g−1, and 79.4 mg g−1 for Co(II), and Ni(II), respectively. Our results showed that Mg–Al–Zn mingled oxides can be used as an efficient adsorbent material for removal of heavy metals from industrial wastewater samples.

Biosorption of Pb2 +  and Cd2 +  in a Fixed Bed Column with Immobilised Chorella sp. Biomass

2008 ◽  
Vol 58 (5) ◽  
pp. 1061-1069 ◽  
Author(s):  
Veronica Almaguer Cantu ◽  
Ma Teresa Garza-González ◽  
Javier Rivera de la Rosa ◽  
Jose Angel Loredo-Medrano
Keyword(s):  
Metal Ion ◽  
Fixed Bed ◽  
Langmuir Model ◽  
Ion Concentration ◽  
Orthogonal Collocation ◽  
Pellet Size ◽  
Fixed Bed Column ◽  
Chlorella Sp ◽  
Continuity Equations ◽  
Biosorption Equilibrium

The biosorption of Pb2 +  and Cd2 +  in a fixed bed column by immobilised Chlorella sp. was characterised in a fixed bed column. Effect of initial concentration of Pb2 +  and Cd2 + , pH, and pellet size on the biosorption capacity was studied, at laboratory scale, using a factorial experiment design 23, in a 10 cm height × 1 cm of diameter continuous flow column packed with immobilised biomass. Equilibrium uptake of Pb2 +  and Cd2 + , increased with increasing initial metal ion concentration. It was favoured to pH 5, with a pellet of 5 mm of diameter. Langmuir model described the biosorption equilibrium of both metals. The biosorption of each single cation was studied too in a large column (50 cm height × 5 cm of diameter) at bench scale with a range of flow of 40 to 80 mL min−1. The mass transfer coefficient was determined fitting the experimental data to continuity equations that were discretised in the radial terms with orthogonal collocation method.

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