scholarly journals Preliminary study on the upcycle of non-structural construction and demolition waste for waste cleaning

2020 ◽  
Vol 70 (338) ◽  
pp. 220
Author(s):  
P. Chen ◽  
X. Chen ◽  
Y. Wang ◽  
P. Wang
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
High Surface ◽  
Exchange Capacity ◽  
Construction And Demolition Waste ◽  
Demolition Waste ◽  
Ion Exchange Capacity ◽  
Surface Areas ◽  
Preliminary Study

This study proposes a method to convert non-structural calcium-rich construction and demoli­tion waste fines into adsorbents of heavy metal ions by mixing waste fines with diammonium hydrogen phos­phate solution to produce hydroxyapatite, which has high surface areas and excellent ion-exchange capacity with heavy metal ions. As a result, environmental polluting waste is converted into environmentally cleaning material. Waste putty powders was chosen as the representative waste to investigate the detailed formation process of hydroxyapatite and the key reaction parameters of the reaction. Results showed that hydroxyapatite can be pro­duced on waste putty particles. Higher ageing temperatures or longer ageing duration are beneficial to the yield and crystallinity of the produced hydroxyapatite. Adsorption testing confirmed that Ni2+ can replace Ca2+ in the hydroxyapatite lattice, leading to the formation of a new crystal, arupite (Ni3(PO4)2•8H2O), and contributing to a modest adsorption capacity for Ni2+ (15 mg/g) for the hydroxyapatite-containing waste putty.

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+).

Studies on Synthesis and Ion Exchange Properties of Sulfonated Polyvinyl Alcohol/Phosphomolybdic Acid Composite Cation Exchanger

2016 ◽  
Vol 875 ◽  
pp. 149-155
Author(s):  
Mukta Rathore ◽  
Ahmad Jahan Khanam ◽  
Vikas Gupta
Keyword(s):  
Heavy Metal ◽  
Ion Exchange ◽  
Polyvinyl Alcohol ◽  
Metal Ions ◽  
Metal Ion ◽  
Heavy Metal Ions ◽  
Ion Pairs ◽  
Phosphomolybdic Acid ◽  
Exchange Capacity ◽  
Ion Exchange Capacity

In this study, sulfonated polyvinyl alcohol/phosphomolybdic acid composite cation exchange membrane was prepared by solution casting method. Some of the ionb exchange peroperties such as ion exchange capacity for alkali and alkali metal ions, effect of temperature on ion exchange capacity, elution behavior, effect of eluent concentration, distribution coefficient were studied. On the basis of selectivity coefficient values some important binary separation of heavy metal ion pairs such as Hg (II)-Zn (II), Hg (II)-Cd (II), Hg (II)-Ni (II) and Hg (II)-Cu (II) were carried out. It was observed that elution of heavy metal ions depends upon the metal-eluting ligand stability. Mercury remained in column for a longer time than that of other heavy metal ions. The separations are fairly sharp and recovery of Hg (II) ions is quantitative and reproducible.

scholarly journals Recent Progress in Heavy Metal Ion Decontamination Based on Metal–Organic Frameworks

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1481
Author(s):  
Yajie Chen ◽  
Xue Bai ◽  
Zhengfang Ye
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Metal Ion ◽  
High Surface ◽  
Metal Organic Frameworks ◽  
Environmental Safety ◽  
Surface Areas ◽  
Effective Removal ◽  
Pore Size Distributions ◽  
Metal Organic

Heavy metals are inorganic pollutants which pose a serious threat to human and environmental safety, and their effective removal is becoming an increasingly urgent issue. Metal–organic frameworks (MOFs) are a novel group of crystalline porous materials, which have proven to be promising adsorbents because of their extremely high surface areas, optimizable pore volumes and pore size distributions. This study is a systematic review of the recent research on the removal of several major heavy metal ions by MOFs. Based on the different structures of MOFs, varying adsorption capacity can be achieved, ranging from tens to thousands of milligrams per gram. Many MOFs have shown a high selectivity for their target metal ions. The corresponding mechanisms involved in capturing metal ions are outlined and finally, the challenges and prospects for their practical application are discussed.

Bio-inspired surface-functionalization of graphene oxide for the adsorption of organic dyes and heavy metal ions with a superhigh capacity

2014 ◽  
Vol 2 (14) ◽  
pp. 5034-5040 ◽  
Author(s):  
Zhihui Dong ◽  
Dong Wang ◽  
Xia Liu ◽  
Xianfeng Pei ◽  
Liwei Chen ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Graphene Oxide ◽  
Synergistic Effect ◽  
Metal Ions ◽  
Surface Area ◽  
Surface Functionalization ◽  
Heavy Metal Ions ◽  
Organic Dyes ◽  
High Surface ◽  
High Surface Area

By utilizing the synergistic effect of poly-dopamine (PD) with functional groups and graphene oxide (GO) with a high surface area, a series of sub-nano thick PD layer coated GO (PD/GO) composites were fabricated and used for effectively decontaminating wastewater.

scholarly journals Sorption of lead and cadmium ions from aqueous solutions using modified zeolite

2018 ◽  
pp. 16-22
Author(s):  
Madina Telkhozhayeva ◽  
Gulziya Seilkhanova ◽  
A. Rakhym ◽  
Ainur Imangaliyeva ◽  
Dina Akbayeva
Keyword(s):  
Heavy Metal ◽  
Aqueous Solutions ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Exchange Capacity ◽  
Static Exchange Capacity ◽  
Cadmium Ions ◽  
Modified Zeolite ◽  
Lead And Cadmium ◽  
Static Conditions

The processes of lead and cadmium ions sorption by modified zeolite of Chankanai deposit were studied. Chitosan was used as a surface modifier due to its properties: nontoxicity, biodegradability and biocompatibility. The adsorption process was carried out at room temperature (295 K) and pH 7 under static conditions. The synthesized sorbent has been characterized by scanning electron microscopy (SEM), elemental analysis; the concentrations of Pb(II) and Cd(II) ions before and after adsorption were determined using atomic absorption spectroscopy (AAS). The Si/Al ratio of the zeolite was found to be 1.66, which showed the prospects of using this material as a source object. The static exchange capacity (SEC) of sorbents and the extraction degree of heavy metal ions were determined and compared. It was found that the removal of heavy metal ions increased with the increase of contact time (removal efficiency was 99.1±1.2% for Pb2+ and 83.4±1.2% for Cd2+). The adsorption capacity values of the modified zeolite for metal ions were (0.86±0.03) mg/g for Cd(II) and (0.68±0.03) mg/g for Pb(II). Chitosan-modified zeolite proved to be an effective adsorbent for removal of lead and cadmium ions from aqueous solutions.

SORPTION MATERIALS BASED ON ALKALI-INSOLUBLE COMPONENTS PEAT AND BROWN COAL FOR WASTEWATER TREATMENT FROM IONS OF HEAVY METAL

2021 ◽  
pp. 175-186
Author(s):  
Natalia S. Pershay ◽  
Yuriy G. Yanuta
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Wastewater Treatment ◽  
Metal Ions ◽  
Organic Compounds ◽  
Brown Coal ◽  
Heavy Metal Ions ◽  
Copper Ions ◽  
Exchange Capacity ◽  
Water Soluble

The problem of environmental pollution with heavy metals is relevant for the Republic of Belarus. One of the ways to remove heavy metals from industrial wastewater is to treat them with sorbents. Sorbents based on peat and brown coal are effective and inexpensive, but their use leads to secondary contamination of the treated environment with water-soluble organic compounds. It is shown that the developed sorption materials based on peat and brown coal residues sorb heavy metal ions (copper, nickel, zinc) and do not pollute the treated medium with water-soluble organic compounds (the COС value of sorption materials does not exceed 5 mg O2/dm3). It was found that the exchange capacity of sorption materials in an acidic medium (pH 2.0) is higher than that of humic acids and is in the range of 0.17–1.38 mmol/g. The use of ultrasonic treatment to increase the exchange capacity of sorption materials makes it possible to increase it by 2.3–3.0 times for copper ions and 2.2 times for zinc ions, which is due to the destruction of large aggregates. The obtained results formed the basis for the development of a technology for obtaining sorption materials for wastewater treatment from heavy metal ions.

scholarly journals Rapid Preparation of Biosorbents with High Ion Exchange Capacity from Rice Straw and Bagasse for Removal of Heavy Metals

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Supitcha Rungrodnimitchai
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Ion Exchange ◽  
Rice Straw ◽  
Heavy Metal Ions ◽  
Exchange Resin ◽  
Ion Exchange Resin ◽  
Exchange Capacity ◽  
Ion Exchange Capacity ◽  
Removal Of Heavy Metals

This work describes the preparation of the cellulose phosphate with high ion exchange capacity from rice straw and bagasse for removal of heavy metals. In this study, rice straw and bagasse were modified by the reaction with phosphoric acid in the presence of urea. The introduced phosphoric group is an ion exchangeable site for heavy metal ions. The reaction by microwave heating yielded modified rice straw and modified bagasse with greater ion exchange capacities (∼3.62 meq/g) and shorter reaction time (1.5–5.0 min) than the phosphorylation by oil bath heating. Adsorption experiments towards Pb2+, Cd2+, and Cr3+ions of the modified rice straw and the modified bagasse were performed at room temperature (heavy metal concentration 40 ppm, adsorbent 2.0 g/L). The kinetics of adsorption agreed with the pseudo-second-order model. It was shown that the modified rice straw and the modified bagasse could adsorb heavy metal ions faster than the commercial ion exchange resin (Dowax). As a result of Pb2+sorption test, the modified rice straw (RH-NaOH 450W) removed Pb2+much faster in the initial step and reached 92% removal after 20 min, while Dowax (commercial ion exchange resin) took 90 min for the same removal efficiency.

scholarly journals Preparation and Application of Bismuth/MXene Nano-Composite as Electrochemical Sensor for Heavy Metal Ions Detection

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 866 ◽  
Author(s):  
Ying He ◽  
Li Ma ◽  
Liya Zhou ◽  
Guanhua Liu ◽  
Yanjun Jiang ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Surface Area ◽  
Heavy Metal Ions ◽  
High Surface ◽  
High Surface Area ◽  
Effective Surface ◽  
Nano Composite ◽  
Environmental Friendliness ◽  
Metal Ions Detection

A nano-form composite of MXenes (Ti3C2Tx, Tx = -O, -OH, -F) was synthesized through depositing bismuth-nanoparticle (BiNPs) onto Ti3C2Tx sheets. Because of the preventive effect of the two-dimensional layered structure of Ti3C2Tx, the nanoparticles of Bi were uniform and well attached on the Ti3C2Tx. The obtained BiNPs/Ti3C2Tx nano-composite was applied for sensors construction of electrochemical detecting of Pb2+ and Cd2+ heavy metal ions. The produced BiNPs@Ti3C2Tx-based sensor showed high effective surface area and excellent conductivity. Also, the BiNPs were efficient for anodic-stripping voltammetric to detect heavy metal ions. After conditions optimization, the BiNPs@Ti3C2Tx nano-sensor could detect Pb2+ and Cd2+ simultaneously and the detection limits were 10.8 nM for Pb2+ and 12.4 nM for Cd2+. The BiNPs@Ti3C2Tx was promising for detecting heavy metal ions due to their high surface area, fast electron-transfer ability, environmental friendliness, and facial preparation.

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