Reaction of lead ions with hydroxylapatite granules

2008 ◽  
Vol 62 (5) ◽  
Author(s):  
Madjid Hadioui ◽  
Patrick Sharrock ◽  
Mohamed-Oimar Mecherri ◽  
Véronique Brumas ◽  
Marina Fiallo
Keyword(s):  
Heavy Metal ◽  
Lead Concentration ◽  
Aqueous Media ◽  
Absorption Capacity ◽  
Lead Ions ◽  
Flow Conditions ◽  
Lead Phosphate ◽  
Surface Areas ◽  
Heavy Metal Sorption ◽  
Phosphate Source

AbstractIn the effort to improve the performance of hydroxylapatite (HA) in removing lead ions from aqueous solutions, millimeter-sized granules with 50 % porosity were synthesized. Such HA particles, after drying at 100°C, or heating at 800°C or 1100°C, exhibited the specific surface areas of 50 m2 g−1, 25 m2 g−1, and 5 m2 g−1, respectively. It was found that heavy metal sorption capacity of HAs can be related to their surface area. Non-calcined granules were difficult to handle and easy to crush. Hardened granules showed heavy metal absorption on their outer surfaces. Absorption capacity of sintered HA particles towards lead was lower but adsorbed lead ions were spread inside the porous structure of HA granules more evenly. Under flow conditions, lead ions were captured by HA at a rate of 0.5 mg g−1 min−1. Small lead phosphate aggregates were released from the HA sorbent together with calcium ions. Size of the aggregates depended on the lead concentration and ranged from 1–50 μm in diameter; the aggregates could be removed by ultrafiltration. Results show that porous hardened HA granules can be used as an efficient phosphate source for the immobilization of lead ions from aqueous media. Organic ligands tend to interfere with the water purification procedure.

ASSESSING THE RELATIONS BETWEEN THE SURFACE PROPERTIES OF BIOCHARS AND HEAVY METAL SORPTION

2020 ◽  
Author(s):  
Amy Lam ◽  
◽  
Todd Longbottom ◽  
Nelli K. Bodiford ◽  
Omar R. Harvey
Keyword(s):  
Heavy Metal ◽  
Surface Properties ◽  
Metal Sorption ◽  
Heavy Metal Sorption

scholarly journals Complex Aerogels Generated from Nano-Polysaccharides and Its Derivatives for Oil–Water Separation

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1593 ◽  
Author(s):  
Hajo Yagoub ◽  
Liping Zhu ◽  
Mahmoud H. M. A. Shibraen ◽  
Ali A. Altam ◽  
Dafaalla M. D. Babiker ◽  
...  
Keyword(s):  
Guar Gum ◽  
Corn Oil ◽  
Cellulose Nanofibers ◽  
Aqueous Media ◽  
Three Dimensional ◽  
Absorption Capacity ◽  
Water Contact ◽  
Water Separation ◽  
Oil Water Separation ◽  
Oil Water

The complex aerogel generated from nano-polysaccharides, chitin nanocrystals (ChiNC) and TEMPO-oxidized cellulose nanofibers (TCNF), and its derivative cationic guar gum (CGG) is successfully prepared via a facile freeze-drying method with glutaraldehyde (GA) as cross-linkers. The complexation of ChiNC, TCNF, and CGG is shown to be helpful in creating a porous structure in the three-dimensional aerogel, which creates within the aerogel with large pore volume and excellent compressive properties. The ChiNC/TCNF/CGG aerogel is then modified with methyltrichlorosilane (MTCS) to obtain superhydrophobicity/superoleophilicity and used for oil–water separation. The successful modification is demonstrated through FTIR, XPS, and surface wettability studies. A water contact angle of 155° on the aerogel surface and 150° on the surface of the inside part of aerogel are obtained for the MTCS-modified ChiNC/TCNF/CGG aerogel, resulting in its effective absorption of corn oil and organic solvents (toluene, n-hexane, and trichloromethane) from both beneath and at the surface of water with excellent absorption capacity (i.e., 21.9 g/g for trichloromethane). More importantly, the modified aerogel can be used to continuously separate oil from water with the assistance of a vacuum setup and maintains a high absorption capacity after being used for 10 cycles. The as-prepared superhydrophobic/superoleophilic ChiNC/TCNF/CGG aerogel can be used as a promising absorbent material for the removal of oil from aqueous media.

Robust transparent mesoporous silica membranes as matrices for colorimetric sensors

RSC Advances ◽  
2015 ◽  
Vol 5 (21) ◽  
pp. 16549-16553 ◽  
Author(s):  
Donghun Kim ◽  
Bradley F. Chmelka
Keyword(s):  
Heavy Metal ◽  
Mesoporous Silica ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Colorimetric Detection ◽  
High Surface ◽  
Silica Membranes ◽  
Surface Areas ◽  
Functionalized Mesoporous Silica ◽  
Colorimetric Sensors

Transparent functionalized mesoporous silica membranes have been prepared with high surface areas (∼500 m2 g−1) that exhibit high sensitivities for colorimetric detection and sensing of dilute heavy-metal ions (e.g., Pb2+).

scholarly journals A systematic study for removal of heavy metals from aqueous media using Sorghum bicolor: an efficient biosorbent

2018 ◽  
Vol 77 (10) ◽  
pp. 2355-2368 ◽  
Author(s):  
Khalida Naseem ◽  
Zahoor H. Farooqi ◽  
Muhammad Z. Ur Rehman ◽  
Muhammad A. Ur Rehman ◽  
Robina Begum ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Aqueous Media ◽  
Review Article ◽  
Isotherm Models ◽  
Adsorption Efficiency ◽  
Adsorption Isotherm Models ◽  
Removal Of Heavy Metals

Abstract This review is based on the adsorption characteristics of sorghum (Sorghum bicolor) for removal of heavy metals from aqueous media. Different parameters like pH, temperature of the medium, sorghum concentration, sorghum particle size, contact time, stirring speed and heavy metal concentration control the adsorption efficiency of sorghum biomass for heavy metal ions. Sorghum biomass showed maximum efficiency for removal of heavy metal ions in the pH range of 5 to 6. It is an agricultural waste and is regarded as the cheapest biosorbent, having high adsorption capacity for heavy metals as compared to other reported adsorbents, for the treatment of heavy metal polluted wastewater. Adsorption of heavy metal ions onto sorghum biomass follows pseudo second order kinetics. Best fitted adsorption isotherm models for removal of heavy metal ions on sorghum biomass are Langmuir and Freundlich adsorption isotherm models. Thermodynamic aspects of heavy metal ions adsorption onto sorghum biomass have also been elaborated in this review article. How adsorption efficiency of sorghum biomass can be improved by different physical and chemical treatments in future has also been elaborated. This review article will be highly useful for researchers working in the field of water treatment via biosorption processing. The quantitative demonstrated efficiency of sorghum biomass for various heavy metal ions has also been highlighted in different sections of this review article.

Removal of lead ions from water using thiophene-functionalized metal–organic frameworks

2020 ◽  
Vol 56 (2) ◽  
pp. 237-240 ◽  
Author(s):  
Alissa R. Geisse ◽  
Chrispus M. Ngule ◽  
Douglas T. Genna
Keyword(s):  
Metal Organic Frameworks ◽  
Lead Ions ◽  
Flow Conditions ◽  
Metal Organic

We report the use of thiophene containing MOFs, notably DUT-67, for the removal of Pb2+ ions from water under both batch and flow conditions with a max loading of 98.5 mg Pb2+ per g MOF via potential 6π-η5-thiophene-Pb2+ coordination.

Subsupercritical Water Generated by Inductive Heating Inside Flow Reactors Facilitates the Claisen Rearrangement

Synlett ◽  
2020 ◽  
Vol 31 (19) ◽  
pp. 1942-1946
Author(s):  
Andreas Kirschning ◽  
Mona Oltmanns
Keyword(s):  
Organic Solvents ◽  
High Temperatures ◽  
Claisen Rearrangement ◽  
Flow System ◽  
Aqueous Media ◽  
Inductive Heating ◽  
Flow Conditions ◽  
Flow Reactors

AbstractClaisen rearrangement of electron-deficient O-allylated phenols, including fluorine-modified phenols, is facilitated in aqueous media at high temperatures and pressures under flow conditions, as opposed to organic solvents. The O-allylation of phenols can be coupled with the Claisen rearrangement in an integrated flow system.

scholarly journals Heavy Metal Sorption by Sludge-Derived Biochar with Focus on Pb2+ Sorption Capacity at μg/L Concentrations

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1559
Author(s):  
Ida Sylwan ◽  
Hanna Runtti ◽  
Lena Johansson Westholm ◽  
Henrik Romar ◽  
Eva Thorin
Keyword(s):  
Experimental Data ◽  
Heavy Metals ◽  
Heavy Metal ◽  
Sorption Capacity ◽  
Municipal Wastewater ◽  
Metal Removal ◽  
Metal Exposure ◽  
Isotherm Models ◽  
Metal Sorption ◽  
Heavy Metal Sorption

Municipal wastewater management causes metal exposure to humans and the environment. Targeted metal removal is suggested to reduce metal loads during sludge reuse and release of effluent to receiving waters. Biochar is considered a low-cost sorbent with high sorption capacity for heavy metals. In this study, heavy metal sorption to sludge-derived biochar (SDBC) was investigated through batch experiments and modeling and compared to that of wood-derived biochar (WDBC) and activated carbon (AC). The aim was to investigate the sorption efficiency at metal concentrations comparable to those in municipal wastewater (<1 mg/L), for which experimental data are lacking and isotherm models have not been verified in previous works. Pb2+ removal of up to 83% was demonstrated at concentrations comparable to those in municipal wastewater, at pH 2. SDBC showed superior Pb2+ sorption capacity (maximum ~2 mg/g at pH 2) compared to WDBC and AC (<0 and (3.5 ± 0.4) × 10−3 mg/g, respectively); however, at the lowest concentration investigated (0.005 mg/L), SDBC released Pb2+. The potential risk of release of other heavy metals (i.e., Ni, Cd, Cu, and Zn) needs to be further examined. The sorption capacity of SDBC over a metal concentration span of 0.005–150 mg Pb2+/L could be predicted with the Redlich–Peterson model. It was shown that experimental data at concentrations comparable to those in municipal wastewater are necessary to accurately model and predict the sorption capacity of SDBC at these concentrations.

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