Removal Efficiency Of Pb Research Articles

Removal of Hazardous Materials from Residential and Commercial Liquid Waste Using Solid Sorbents

Among various pollutants, wastewater consists of toxic or carcinogenic heavy metals such as lead (Pb), zinc (Zn), and copper (Cu). In this study, the contamination of heavy metals in residential (Domestic) and commercial (Car-wash centre) effluents from urban area of Quetta has been investigated using atomic absorption spectroscopy. The collected liquid effluent was passed through sorbents in vertical flow. The combined batch of Fly ash and Sawdust (adsorbents) showed high sorption capacity 0.0000424 mg·g -1 for lead (residential liquid waste) and 0.0000012 mg·g -1 for Cu (commercial liquid waste). The moderate partition coefficients were 0.001247 (Pb) and 0.000005 (Cu) mol·kg -1 ·Pa -1 for residential and commercial waste respectively. The highest removal efficiency of lead (99.763%) for residential effluent showed the breakthrough at 0.002. Thus, the sorbents used have significantly removal efficiency for Pb, moderate for Zn, and low for Cu. The effluent passed from designed filter media may be greatly effective for washing, cleaning and irrigation purpose.

Effect of ZnO nanoparticles on Zn, Cu, and Pb dissolution in a green bioretention system for urban stormwater remediation

Stormwater runoff from urban and suburban areas can carry hazardous pollutants directly into aquatic ecosystems. These pollutants, such as metals, nutrients, aromatic hydrocarbons, pesticides, and pharmaceuticals, are very toxic to aquatic organisms. Recently, significant amounts of zinc oxide engineered nanoparticles (ZnO-NPs) have been detected in urban stormwater and its bioretention systems. This raises concerns about a potential increase of stormwater toxicity and reduced performance of the treatment infrastructures. To tackle these issues, we developed a simple, low-cost bioretention system to remediate stormwater and retain ZnO-NPs. This system retained up to 73% Zn, 66% Cu, and >99% Pb. However, the removal efficiency for Pb was lower after adding ZnO-NPs to the system, possibly due to the remobilization of Pb phosphates. The effect of ZnO-NPs on stormwater toxicity and metal accumulation in wetland plants was also evaluated.

Remediation of Metal Contaminated Simulated Acid Mine Drainage Using a Lab-Scale Spent Mushroom Substrate Wetland

The performance of an innovative pilot-scale spent mushroom substrate wetland for the attenuation of simulated acid mine drainage (SAMD) similar in composition to wastewater from the Irish mining region in Avoca, Co. Wicklow was investigated. The small-scale surface flow wetland, consisting of four cells in triplicate, measuring 0.46 m in width, 0.622 m in length and 0.489 m in depth, received approximately 4.32 l/day of simulated acid mine drainage. Over a period of 800 days, average removal efficiencies of Al (99 %), Zn (99 %), Cu (99 %), Fe (97 %) and Pb (97 %) were recorded, with no removal noted for Mn. These high removal rates were found to be comparable with other published results and in most cases surpassed removal rates of published results. Despite the reduction in pH and alkalinity over the duration of the trial, the rise in sulphate concentrations and the production of ammonia within the system were of concern, especially if a similar treatment system was utilised on a large scale basis. Temperature was also found to have an effect on metal removal rates, with poor removal rates recorded at low temperature events (< 1oC). The high metal removal rates of the system still make it a very attractive and environmentally sustainable remediation technology, which could be further expanded to include other passive treatment technologies, to enhance and increase the longevity of the system.

Phytoremediation: A Novel Strategy for the Removal of Heavy Metals from the Offshore of Lake Hawassa using Typha Latifolia L

ABSTRACT Aquatic macrophytes absorb a number of pollutants from where they are growing and thus, they can be used as a tool for the removal of pollutants from the aquatic ecosystem. Therefore, the aim of this study was to evaluate heavy metals (Hg, Cr, Zn, Cd, and Pb) removal efficiency of Typha latifolia L. from the offshore of Hawassa Lake, Ethiopia. Based on the potential exposure of the lake to different sources of pollutants, six sampling sites were selected, and then T. latifolia and composite plant samples were collected from each sampling site and transported to Addis Ababa Environmental Protection Agency (EPA) laboratory for analysis. The results showed that significantly (P < .05) higher heavy metal concentration was recorded in T. latifolia than in composite plant samples, particularly samples collected from S2, S4, and S5. Moreover, significantly (P < .05) higher heavy metal concentration was found in the root parts of the T, latifolia than its shoot. The concentration of heavy metals recorded in this study has slightly exceeded the level set by the WHO guideline. In addition, medium to very high correlations were recorded for some heavy metal pairs as well as with some physicochemical parameters (e.g. pairs of Zn/Pb, Cd/Pb, EC, and pH with most heavy metals).In conclusion, T. latifolia have shown promising potential for the removal of Zn, Pb and Cd, while composite macrophytes samples for Hg and Cr. The shoot part of T. latifolia has a relatively better capacity to remove Cr, while the root is for Hg, Zn, Cd and Pb. These results indicated the suitability of the plant for phytoremediation, and the usefulness of the technique as an option for improving the water quality of the lake by removing those heavy metals from the lake offshore.

Activated carbon coupled with citric acid in enhancing the remediation of Pb-Contaminated soil by electrokinetic method

Soil contaminated by heavy metals has received widespread attention, and the efficient removal of heavy metals remains a challenge. A novel process for enhancing the electrokinetic (EK) performance to remediate the Pb-contaminated soil was proposed by coupling the activated carbon (AC) and citric acid (CA). The synergetic effect of AC and CA was found to significantly improve the Pb removal efficiency by EK method. The Pb removal efficiency was only about 4% after 480 h treatment in the traditional EK cell, and it was improved greatly to ~15% and 58% after adding CA and CA + AC, respectively. The introduction of CA caused more soluble Pb complexes to be formed through carboxyl and hydroxyl groups, which accelerated the dissolution and desorption of Pb in soil. However, with only CA addition in the EK cell, a high pH of 13 was observed near the cathode causing the metal precipitation near the cathode, thereby blocking soil pores and hindering the remediation process. With the assistance of AC, a more uniform pH distribution was developed and the pH in the whole EK cell was maintained below 10, which was beneficial for the transportation of Pb. Furthermore, the removed Pb was retained in the AC without generating Pb-containing wastewater to realize the cleaner production of the remediation process. In addition, this study developed tubular electrodes without additional electrolytic cells, which largely simplified the EK remediation system and can be more easily deployed in the field test for real-world application.

The potential of water hyacinth in the phytoremediation of industrial wastewater

In this study, the potential of water hyacinth in the phytoremediation of simulated wastewater containing copper (Cu) and lead (Pb) was studied. Locally available water hyacinth was collected from an uncontrolled environment. The prepared samples were segregated into three different parts (i.e., leaf, stem, and root), ground into powder, and used as the adsorbent for heavy metal removal. Acid digestion method was utilized for the preparation of the samples prior to atomic absorption spectrometry (AAS), and AAS was performed to determine the heavy metal concentration for each plant part. Based on the baseline study for identifying the heavy metal content in raw water hyacinth, Cu and Pb mostly accumulated in the root. The pH of simulated wastewater dropped upon the addition of Cu, and the pH gradually increased to 7 after day 7 onward. The overall removal efficiency of Cu decreased from 98.7% to 91.6% as the Cu concentration increased from 1 mg/L to 5 mg/L. Meanwhile, the overall removal efficiency of Pb decreased from 73.6% to 31.3% as the Pb concentration increased from 250 mg/L to 750 mg/L. Thus, water hyacinth is useful for treating wastewater containing heavy metals, particularly Cu and Pb.

인산활성화 옥수수 줄기를 이용한 수용액에서의 납의 효율적인 흡착

The purpose of this study is to compare and analyze the removal efficiency of Pb(II) through the phosphorylation of corn stalk and natural corn stalk in aqueous solution. After the phosphorylation of corn stalks (PCS), the pHpzc decreased to 3.82, confirming the attachment of acidic functional groups onto the surface of the corn stalks. The pseudo-second-order and Langmuir isothermal models were found to be suitable for modeling the adsorption kinetics and conducting isothermal experiments of the adsorption of Pb(II) onto PCS. The maximum adsorption capacity of Langmuir was 182.76 mg/g. The adsorption process involving PCS was close to physical adsorption, and the adsorption efficiency increased as the temperature increased. According to a Fourier transform infrared analysis, phosphorylation increased the number of carboxyl groups (-COOH) on the corn stalks. In addition, the phosphoric acid group expanded the pore shape of the adsorbent to increase the exposure of anions to the surface. Consequently, the adsorption efficiency of Pb(II), a cationic ion, onto PCS increased.

Adsorption of metals in oil sands process water by a biochar/iron oxide composite: Influence of the composite structure and surface functional groups

In this work, anaerobic sludge from a wastewater treatment plant was used to prepare a sludge-based biochar/iron oxide (B-FeOx) adsorbent. The B-FeOx adsorbent was successfully used to remove metals, including Cr, Cu, Se and Pb from oil sands process water (OSPW) for the first time. Compared with biochar or FeOx alone, a higher removal efficiency of Cr (80.79%±3.44%), Cu (98.21%±0.25%), Se (88.82%±0.31%) and Pb (90.96%±1.86%) was obtained using the B-FeOx composite. The high removal efficiency was attributed to the improved specific surface area and pore volume of the B-FeOx composite, which increased by about 5.9 and 5.7 times, respectively, when compared to biochar. In addition, functional groups in the composite, such as C-O, C = O, O–H, and some iron-bound functional groups, played an important role in the improvement of the removal efficiency of metals. Moreover, the adsorption process was best modelled by the pseudo-second order kinetic model and Langmuir model. Intraparticle diffusion modelling for adsorption of the four metals using B-FeOx composite resulted in two distinct regions: film and pore diffusion. This study provides the details of a low cost, effective, and environmentally friendly adsorbent for the removal of metals from real OSPW.

Removal of heavy metals from abandoned smelter contaminated soil with poly-phosphonic acid: Two-objective optimization based on washing efficiency and risk assessment

Soil washing is a feasible technology to achieve rapid remediation and reuse of contaminated sites. However, there is still a need to seek eco-friendly and low-cost washing reagents. In this study, a two-objective optimization method has been proposed to investigate the removal efficiencies of eluents and risk of migration (risk assessment code, RAC) of residual metal simultaneously when soil Cd and Pb washed by polyamino polyether methylene phosphonate (PPMP) and bis (hexamethylene triamine penta (methylenephosphonic acid)) (BHMT). The coefficients of determination of the equations proved that D-optimal mixture design could be used for optimizing and modeling of the two objectives during soil washing. And their single-factor (concentration, solution pH, or contact time) and interaction effects indicated that PPMP react with Cd and Pb through chelation at strong acid in soil, whereas acid dissolution effect would convert the stable form of soil Pb into unstable form. BHMT could rapidly remove more acid-soluble fractions of Cd and Pb through the electric double layer adsorption, and is favorable under neutral conditions. Moreover, the optimum removal efficiencies of soil Cd and Pb were 83.98 and 41.29%, and RACs were 45.1 and 5.16% respectively in PPMP washing; accordingly, 69.31 and 28.11% of optimum removals and 32.45 and 0.98% of RACs for soil Cd and Pb were obtained in BHMT leaching. Therefore, PPMP and BHMT are two feasible remediation reagents of the abandoned industrial soils contaminated by heavy metals.

Calixresorcin[4]arene-Mediated Transport of Pb(II) Ions through Polymer Inclusion Membrane.

A facilitated transport of Pb(II) through polymer inclusion membrane (PIM) containing 1,8,15,22-tetra(1-heptyl)-calixresorcin[4]arene and its tetra- and octasubstituted derivatives containing phosphoryl, thiophosphoryl or ester groups as an ion carrier was investigated. The efficiency of Pb(II) removal from aqueous nitrate solutions was considered as a function of the composition of membrane (effect of polymer, plasticizer, and carrier), feed (effect of initial metal concentration and presence of other metal ions) and stripping phases, and temperature of the process conducting. Two kinetic models were applied for the transport description. The highest Pb(II) ions removal efficiency was obtained for the membrane with tetrathiophosphorylated heptyl-calixresorcin[4]arene as an ion carrier. The activation energy value, found from Eyring plot to be equal 38.7 ± 1.3 kJ/mol, suggests that the transport process is controllable both by diffusion and chemical reaction. The competitive transport of Pb(II) over Zn(II), Cd(II), and Cr(III) ions across PIMs under the optimal conditions was also performed. It was found that the Cr(III) ions’ presence in the feed phase disturb effective re-extraction of Pb(II) ions from membrane to stripping phase. Better stability of PIM-type than SLM-type membrane was found.

Rare earth real wastewater treatment by pilot scale using new concept continuous treatment process

Rare earth (RE) containing radioactive species and a variety of toxic pollutants The treatment of real wastewater is very important for environmental protection. In this study, a new concept of continuous process consisting of precipitation, adsorption, and oxidation was developed without the use of chemicals. In the sedimentation step, waste oyster shell(WOS) and a PE tube diffuser(PE250) containing Na2S (PECa/S), PECa/S were prepared, which were used to precipitate heavy metals with a removal efficiency of 97% or more. In the adsorption step, fluorine (F), arsenic (As), and thorium (Th) were precipitated and removed when heavy metals were removed using coal mine drainage sludge (CMDS) and an adsorbent (PUCMDS) made of polyurethane (PU). Running a semi and pilot scale continuous process using PECa/S, PUCMDS and O3/HC systems resulted in a semi and pilot scale operating period of 120 and 62 days, and 60.26, 797.84, 46.94, 78.62 g, and 7.120 kg and 266.35, 42556.8, 191.95, 3108.43 g and 629.84 kg for As, F, Th, Pb and CODcr has been removed respectively. In addition, the removal efficiencies of As, F, Th, Pb and CODcr were 99.75, 99.98, 93.60, 99.99, and 88.82%, respectively, when treating real RE wastewater using the pilot scale system. Without the use of agitated reactors and regulators, the new concept of continuous process can effectively treat RE real wastewater, and the quality of the process outlet has met the pollutant limits recommended by EPA and China for irrigation.

Effect of amendments (lime–zeolite–biochar) on the immobilization of Cd and Pb in a contaminated acidic soil

An incubation experiment was carried out to study the remediation effect of lime, zeolite and biochar under different ratios on cadmium (Cd) and lead (Pb) contaminated soil. Soil pH, organic carbon (SOC), bioavailability and mobility of Cd and Pb were investigated. The results indicated that combined application of lime, zeolite and biochar can significantly increase soil pH, the increment was from 0.15 to 0.76. Compared to the control treatment, the concentrations of CaCl2-, TCLP-Cd and Pb significantly decreased in all amended treatments. Considering the soil environmental quality and immobilization efficiency, the ratio of lime, zeolite and biochar was determined to be 1:2:2. The application rate of combined amendment (lime:zeolite:biochar=1:2:2) had obvious effect on soil pH, SOC and removal efficiency of Cd and Pb, promoting the acid soluble fractions of Cd and Pb to residual fractions, especially in higher application rate (5.0% and 10.0%). However, there was no significant difference when the application rate exceeded 5.0%. Therefore, it was suggested that the application rate of combined amendment (lime:zeolite:biochar=1:2:2) could be 5.0% in short-term soil remediation.

Continuous and efficient immobilization of heavy metals by phosphate-mineralized bacterial consortium

Traditional sewage treatment technology cannot remove heavy metals, which needs to be improved urgently. Lysinibacillus with the function of bio-mineralization was screened and loaded on granular sludge to form a phosphate-mineralized bacterial consortium, which demonstrated the ability of self-regulating pH and automatic solid-liquid separation. Heavy metals could be fixed on the bacterial consortium to produce stable and harmless phosphate minerals. The highest removal efficiency of Pb(Ⅱ), Cd(Ⅱ), and Ni(Ⅱ) were 97.9%, 70%, and 40%, respectively. Organic matter and other metal ions in actual polluted water had little effect on the Pb(Ⅱ) removal efficiency. Mechanism analysis was conducted through 3D-EEM, XRD, SEM-EDS, XPS, FTIR, and high-throughput sequencing analyses. The bacterial consortium was a multi-species coexistence system, but Lysinibacillus played a major role in removing Pb(Ⅱ). C-O and O-H bonds of tyrosine and phosphorous organics were broken by enzyme catalysis and the metal-oxygen bond (Pb-O) was formed. Mineral crystals in the reactor accumulated, transforming from the initial phase non-crystalline structure to the metaphase Pb3(PO4)2 and eventually to the Pb5(PO4)3OH. This research obtained a promising technique for immobilizing Pb(Ⅱ) or other hazardous metals continuously and efficiently.

Efficient Pb (II) removal from wastewater by TEG coated Fe3O4 ferrofluid

Tri-ethylene glycol (TEG) coated Fe3O4 nanoparticles ferrofluid were used for Pb (II) removal from simulated wastewater. The samples were synthesized using a modified co-precipitation method. The prepared samples were characterized by different techniques including X-ray diffraction, Rietveld method, FTIR, FESEM, TEM, VSM, TGA, BET and atomic adsorption experiments. The crystallinity of nanoparticles with a cubic spinel ferrite structure and absence of impurity phases were verified using X-ray diffraction and Rietveld method. The presence of TEG was approved by FTIR and thermogravimetric analysis. The VSM results showed that the bonding between the TEG molecules and ferrite nanoparticles, reduces the surface spin disorder, influences the morphology and magnetization, and consequently increases the Pb (II) removal efficiency to a high value of 97%. The obtained high value of adsorption capacity of q=363.4 mg.g-1 with R= 91 % and q=129.4 mg.g-1 with R=97 %shows effective role of TEG coating on Pb (II) adsorption. The interesting results of this study imply that the TEG coated ferrofluid sample is suitable candidate for practical applications.

Comparative study on different organic acids for promoting Solanum nigrum L. hyperaccumulation of Cd and Pb from the contaminated soil

Organic acids-assisted phytoremediation is a promising strategy to remove metal pollutants from the soil. However, few reports have focused on the mechanisms of organic acids promoting the uptake of heavy metals by hyperaccumulators. In this study, 5 types of organic acids, namely polybasic carboxylic acids, acidic amino acids, acidic plant growth regulators, phosphoric and gluconic acids, were comprehensively investigated the effects on the solubility of Cd and Pb in the soil along with their uptake by Cd hyperaccumulator Solanum nigrum L. The results indicated that the addition of Hydroxyethylidene-1,1-diphosphonic acid (HEDP) and d-Gluconic acid (D-GA) effectively extracted the most of acid-extractable and some of reducible and oxidizable fractions of Cd and Pb in the soil, with the extraction rates of 64.8% and 34.4% for total Cd and 53.6% and 30.0% for total Pb, respectively. HEDP and D-GA significantly increased the accumulations of Cd (57.1% and 35.0%) and Pb (43.4% and 31.9%) by S. nigrum without the inhibition of its biomass, making the great removal efficiencies of Cd (1.35% and 1.16%) and Pb (0.039% and 0.036%) from the soil. The enhanced phytoremediation efficiency of S. nigrum was due to the increase of the extractable Cd and Pb in the rhizosphere but little changes of soil pH and enzyme activities (catalase and urease). Among all of organic acids, HEDP may be an alternative to EDTA because of its characteristics of environmental friendliness and high efficiency.

Agricultural waste of sugarcane bagasse as efficient adsorbent for lead and nickel removal from untreated wastewater: Biosorption, equilibrium isotherms, kinetics and desorption studies

The aim of this study was to evaluate the removal of Pb (II) and Ni (II) from untreated waste water using sugarcane bagasse and possible desorption of the metal ions from the adsorbent for effective re-use. The effects of pH (4-6), temperature (30−70 °C), contact time (30−150 min) and adsorbent dosage (0.3−0.7 g) were examined. Optimum conditions for the removal efficiencies of Pb (89.31 %) and Ni (96.33 %) were pH, 6.0; temperature, 30 °C; contact time, 90 min. and adsorbent dosage, 0.5 g. The maximum monolayer adsorption capacities of Pb (II) and Ni (II) were 1.61 mg/g and 123.46 mg/g respectively, by fitting the equilibrium data to the Langmuir isotherm model. Freundlich isotherm and pseudo second order kinetic models were best fitted for Pb (II) and Ni (II) uptake. Desorption of the metal ions from the metal-loaded bagasse was best performed by HNO3 with removal efficiency of 85.2 %. Therefore, sugarcane bagasse has a high potential for removal of heavy metals from waste water and can be re-used at any time after desorption without losing its efficiency.

Novel insight into the adsorption of Cr(VI) and Pb(II) ions by MOF derived Co-Al layered double hydroxide @hematite nanorods on 3D porous carbon nanofiber network

• A novel MOF derived Co-Al-LDH@Fe 2 O 3 /3DPCNF adsorbents was synthesized. • The hybrid nanocomposites showed excellent adsorption capacities on Cr(VI) and Pb(II). • The adsorption isotherm, kinetics, thermodynamics, and mechanism were discussed in detail. • The composite can be easily recovered by magnet after adsorption process. Metal organic framework (MOF) derived layered double hydroxide (LDHs) are not properly probed in the field of the heavy metal ions adsorption from its aqueous solution, although they demonstrated a high possibility in adsorption. In this report, a Co-Al layered double hydroxide loaded with hematite (α-Fe 2 O 3 )@3D porous carbon nanofiber (Co-Al-LDH@Fe 2 O 3 /3DPCNF) was synthesized by a sequential hydrothermal process. The Co-Al LDH was derived from a Co-metal organic framework. FE-SEM, TEM, FTIR, XPS, and BET characterizations and Cr(VI) and Pb(II) adsorption capacities of the composites were investigated in detail. The super hydrophilic Co-Al-LDH@Fe 2 O 3 /3DPCNF exhibited superfast removal efficiencies for Cr(VI) and Pb(II) with maximum adsorption capacities of 400.40 mg g −1 and 426.76 mg g −1 , respectively. Precipitation, surface complexation, isomorphic substitution, and electron transfer were considered to be the main adsorption mechanisms. Adsorption isotherms were well fitted using the Sips model, and the adsorption thermodynamics demonstrated that the adsorption process is endothermic and spontaneous. The Co-Al-LDH@Fe 2 O 3 /3DPCNF maintained excellent adsorption capacity after ten cycles. The present study provides a new pathway to significantly improve the adsorption performance and stability of LDHs with easy separation from water body.

Development of Biosorbent Derived from the Endocarp Waste of Gayo Coffee for Lead Removal in Liquid Wastewater—Effects of Chemical Activators

This study reports the development of bio-based adsorbent by utilizing coffee endocarp (CE) waste as a raw material for lead (Pb) removal from liquid wastewater. The effect of NaOH and HCl as activation precursors on the characteristics and performance of the resulting adsorbents was investigated. The prepared adsorbents were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray fluorescence (XRF) and Surface Area Analyzer (SAA). The characterization results confirm the positive role of the activation by either NaOH or HCl in enhancing the surface properties of the resulting adsorbents. The chemical activations removed most of impurities leading to smoother surface, pore size enlargement and enhanced surface area to pore volume ratio, which result in an enhanced adsorption capacity and Pb removal efficiency. The raw adsorbent shows 57.7% of Pb removal efficiency and sorption capacity of 174.4 mg/g. On the other hand, after the chemical treatment using HCl and NaOH, the Pb removal efficiencies increased up to 63.9% and 89.86%, with adsorption capacity of 193 and 271.58 mg/g, respectively. Though both activated sorbents demonstrate better adsorption performance compared to the non-activated CE, overall results reveal that the NaOH-activated sorbent offers better characteristic and performance than the HCl-activated sorbent.

Efficient removal of lead and arsenic using macromolecule-carbonized rice husks

The adsorption process using inexpensive adsorbents is one of the methods to remove contaminants from aqueous solutions. Biomass porous carbon based materials are among the most widely used adsorbents in this field. Rice husk is a bio-based adsorbent material for pollutant removal. In this study, the porous carbon material obtained from the rice husk was used for the adsorptive removal of lead (Pb) and arsenic (As) from aqueous solutions. Silica was removed from rice husk structure through the one-step reaction using PTFE. The morphological and crystallographic characteristics of the adsorbent surface were determined by scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The removal efficiency was investigated under different conditions of pH (3–9), contact time (3–90min), adsorbent amount (0.5–6 g/l) and initially adsorbed concentration (10–100 μg/l) by changing the parameters in the adsorption reactions. The Response Surface Method (RSM), a Box-Behnken design (BBD), was used to optimize adsorption of Lead and Arsenic by Rice husk. The removal efficiency was finally calculated using analysis of variance. According to the adsorption analysis results, the removal efficiency of Pb and As in aqueous solutions increased (up to 97%, 85% for Lead and Arsenic) under optimum conditions.

Evaluation of the Properties of Diatomaceous Earth in Relation to Their Performance in the Removal of Heavy Metals from Contaminated Effluents

This research analyzes the behavior of different diatomite from Peru, and their potential use for the removal of heavy metals from contaminated effluents. Seven different diatomites were characterized by X-ray diffraction, X-ray fluorescence, scanning electron microscopy, specific surface area, and cation exchange capacity. The absolute removal and the removal efficiency of Cu, Pb, and Zn were assessed by stirring the diatomite in solutions of known concentration of the contaminant, and then analyzing the solutions by atomic absorption spectroscopy (AA). The results were finally correlated with microstructural, chemical, and physicochemical characteristics of the diatomites. It was found that Peruvian diatomites have potential use for decontamination of heavy metals from contaminated effluents even with their low SiO2 content. Affinity for the studied metals was as follows: Zn > Pb > Cu, with removal percentages as higher than 98% for Zn. No one-to-one relationships were found between the removal efficiency of the studied metals with properties of diatomites. Different parameters must be taken into account at the same time to understand the efficiency of metal removal in polluted waters. In this case, the specific surface area and minor oxides have the greatest effect on the removal efficiency of all metals.