Coupled removal of organic compounds and heavy metals by titanate/carbon nanotube composites

2008 ◽  
Vol 58 (10) ◽  
pp. 1985-1992 ◽  
Author(s):  
Ruey-An Doong ◽  
Li-Fen Chiang
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Organic Compounds ◽  
Heavy Metal Adsorption ◽  
Hydrothermal Conditions ◽  
Surface Areas ◽  
Aspect Ratios ◽  
Adsorption Capacities ◽  
Nanotube Composites ◽  
Carbon Nanotube Composites

The objective of this study was to fabricate 1-dimensional (1-D) nanocomposite materials with high aspect ratios and specific surface areas for the coupled degradation of refractory organic compounds and heavy metals. The 1-D nanomaterials were composed of various ratios of carbon nanotubes (CNT) and titanate nanotubes (TNT) (CNT/TNT). Alkaline hydrothermal method was used to fabricate TNT under various hydrothermal conditions. The morphology changed from nanoparticles/nanosheets, nanotubes, nanowires and then to nanoribbon as the hydrothermal temperatures increased from 60 to 230°C. In addition, the CNT/TNT nanomaterials have a good capability toward heavy metal adsorption. The Langmuirian maximum adsorption capacities of nanomaterials were in the range 83–124 mg/g for Cu2 +  and 192–588 mg/g for Pb2 + , which is superior to that of CNT. The removal efficiency of Cu2 +  by CNT/TNT decreased when 40 mg/L MX5B was due to the complexation of MX5B with Cu2 + . Results obtained in this study clearly show the 1-D CNT/TNT nanomaterials are a promising nano-adsorbent for coupled removal of organic as well as heavy metal ions in solution.

scholarly journals Combined Influence of Low-Grade Metakaolins and Natural Zeolite on Compressive Strength and Heavy Metal Adsorption of Geopolymers

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 486
Author(s):  
Alcina Johnson Sudagar ◽  
Slávka Andrejkovičová ◽  
Fernando Rocha ◽  
Carla Patinha ◽  
Maria R. Soares ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Compressive Strength ◽  
Natural Zeolite ◽  
Metal Adsorption ◽  
Low Grade ◽  
Heavy Metal Adsorption ◽  
Adsorption Model ◽  
X Ray ◽  
Adsorption Capacities

Metakaolins (MKs) prepared from low-grade kaolins located in the Alvarães (A) and Barqueiros (B) regions of Portugal were used as the aluminosilicate source to compare their effect on the compressive strength and heavy metal adsorption of geopolymers. Natural zeolite, an inexpensive, efficient adsorbent, was used as an additive in formulations to enhance geopolymers’ adsorption capacities and reduce MK utilization’s environmental footprint. Geopolymers were synthesized with the replacement of MK by zeolite up to 75 wt.% (A25, B25—25% MK 75% zeolite; A50, B50—50% MK 50% zeolite; A75, B75—75% MK 25% zeolite; A100, B100—100% MK). The molar ratios of SiO2/Al2O3 and Na2O/Al2O3 were kept at 1 to reduce the sodium silicate and sodium hydroxide environmental impact. Geopolymers’ crystallography was identified using X-ray diffraction analysis. The surface morphology was observed by scanning electron microscopy to understand the effect of zeolite incorporation. Chemical analysis using X-ray fluorescence spectroscopy and energy dispersive X-ray spectroscopy yielded information about the geopolymers’ Si/Al ratio. Compressive strength values of geopolymers obtained after 1, 14, and 28 days of curing indicate high strengths of geopolymers with 100% MK (A100—15.4 MPa; B100—32.46 MPa). Therefore, zeolite did not aid in the improvement of the compressive strength of both MK-based geopolymers. The heavy metal (Cd2+, Cr3+, Cu2+, Pb2+, and Zn2+) adsorption tests exhibit relatively higher adsorption capacities of Barqueiros MK-based geopolymers for all the heavy metals except Cd2+. Moreover, zeolite positively influenced divalent cations’ adsorption on the geopolymers produced from Barqueiros MK as B75 exhibits the highest adsorption capacities, but such an influence is not observed for Alvarães MK-based geopolymers. The general trend of adsorption of the heavy metals of both MK-based geopolymers is Pb2+ > Cd2+ > Cu2+ > Zn2+ > Cr3+ when fitted by the Langmuir isotherm adsorption model. The MK and zeolite characteristics influence geopolymers’ structure, strength, and adsorption capacities.

scholarly journals Heavy Metal Adsorption and Release on Polystyrene Particles at Various Salinities

2021 ◽  
Vol 8 ◽  
Author(s):  
Beta Susanto Barus ◽  
Kai Chen ◽  
Minggang Cai ◽  
Rongmao Li ◽  
Huorong Chen ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Adsorption Capacity ◽  
Release Rate ◽  
Heavy Metal Concentration ◽  
Aquatic Environments ◽  
Particle Sizes ◽  
Heavy Metal Adsorption ◽  
Heavy Metal Concentrations ◽  
Adsorption Capacities

Microplastics (MPs) and heavy metals are two major types of pollutants that interact with each other, but they are poorly understood. Polystyrene (PS) is one type of MPs that is often detected in aquatic environments. In this study, we examined the adsorption capacity and release rate of heavy metals with respect to different particle sizes of PS, heavy metals, initial heavy metal concentrations, and salinities. Virgin (new) PS with diameters of 20, 50, 130, and 250 μm was used in this study, and four heavy metals (lead, cadmium, copper, and zinc) were used. The results showed that larger PS particle sizes adsorbed more heavy metals even though it took longer to achieve equilibrium adsorption. An increase in heavy metal concentration caused the adsorption capacity (μg g–1) of PS particles to also increase, but the adsorption rate (%) decreased. Increased salinity of the heavy metal solution resulted in a slower adsorption time and a lower adsorption capacity and release rate from the surface of PS particles. Different heavy metals also had different adsorption capacities. Pb was consistently more highly adsorbed by MPs, followed by Cu, Zn, and Cd. Larger PS sizes released heavy metals faster than smaller PS sizes, and the amounts of heavy metals released were higher. The heavy metal with the highest release rate was Cd, followed by Pb, Cu, and Zn. Finally, our findings highlight the interactions between PS and heavy metals and strongly support that PS particles can act as vectors for heavy metals in aquatic systems.

Organic compounds alter the preference and rates of heavy metal adsorption on ferrihydrite

2021 ◽  
Vol 750 ◽  
pp. 141485
Author(s):  
Maya Engel ◽  
Juan S. Lezama Pacheco ◽  
Vincent Noël ◽  
Kristin Boye ◽  
Scott Fendorf
Keyword(s):  
Heavy Metal ◽  
Organic Compounds ◽  
Metal Adsorption ◽  
Heavy Metal Adsorption

scholarly journals The Effect of Some Soil Amendments (Manure and Biochar) on the Bioaccumulation Capacity of Hexavalent Chromium by Two Species of (Salicornia Persica) and (Salicornia Perspolitana) From Contaminated Soil

2021 ◽  
Author(s):  
Fahime Ashrafi ◽  
Ava heidari ◽  
Mohammad Farzam ◽  
Alireza Karimi ◽  
Malihe Amini
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Organic Compounds ◽  
Hexavalent Chromium ◽  
Photosynthetic Pigments ◽  
Dry Weight ◽  
Manure Treatment ◽  
Chromium Accumulation ◽  
Manure Amendments ◽  
Experimental Treatments

Abstract Heavy metals are among the most dangerous contaminants in the environment. Application of organic compounds and plant species with the ability to accumulate and stabilize heavy metal in their organs is the best option for remediation of these elements in the soil. Therefore, this study aimed to investigate the effects of manure and biochar on the accumulation of heavy metals by Salicornia species. Two species of Salicornia ,including S. persica and S. perspolitana, were cultivated outdoor in experimental pots. The effects of experimental treatments ,including hexavalent chromium concentrations, manure ,and biochar on the two studied species, were investigated. The results indicated a significant effect (P < 0.05) of biochar on the accumulation of heavy metals by two species ,S. persicaand S. perspolitana, so that chromium concentrations in the roots and shoots were 258 and 5.41 mg/kg, respectively. Also, chromium accumulations under manure treatments in the roots and shoots were 334.34 and 9.79 mg/kg, respectively. Plant dry weight and height for both species in manure treatment were higher than control and biochar treatments. S. persica showed higher growth than S. perspolitana species. The content of photosynthetic pigments in both S.persica and S. perspolitana species under biochar treatment was higher than control and manure treatments. In general, one can conclude that the accumulation of chromium in S. perspolitana was higher than in S. persica ,and the application of biochar and manure amendments could stabilize chromium in soil and reduce chromium accumulation in both S. persica and S. perspolitana species.

A review on polypyrrole-coated bio-composites for the removal of heavy metal traces from waste water

2019 ◽  
pp. 152808371987127 ◽  
Author(s):  
Subhankar Maity ◽  
Ashish Dubey ◽  
Supriyo Chakraborty
Keyword(s):  
Waste Water ◽  
Heavy Metals ◽  
Heavy Metal ◽  
Industrial Wastewater ◽  
Waste Water Treatment ◽  
Absorption Properties ◽  
Adsorption Capacities ◽  
Ion Absorption ◽  
Removal Of Heavy Metals ◽  
Day By Day

With the development of industrialization and human activities, discharge of waste water containing heavy metals in the environment is increasing day by day. It causes serious threats to the human civilization and the flora and fauna in this earth. Conducting polymers like polypyrrole and polyaniline can be used for treating wastewater due to their inherent ion absorption properties. This article has been focused on the development of polypyrrole coated bio-composites and their potential about the removal of heavy metals from industrial wastewater. Adsorption process can be successfully employed to remove heavy metals from the wastewater by the treatment of water with polypyrrole-coated composites. It was reported in literature that the polypyrrole and polyaniline-coated adsorbents had good adsorption capacities for Mg, Fe, Cu, Cd, Pb, Zn, and Ni. Polypyrrole-coated saw dust, rice husk, chitin, and cellulosic materials could be able to remove Cr, Fe, Cu, and Zn from wastewater. This method would be a replacement for costly conventional methods of removing heavy metal ions from wastewater. It is expected that this method would be an alternative for waste water treatment which will benefit the industries in future.

Elements of the Inhibition of Nitrifying Bacteria

1982 ◽  
Vol 14 (6-7) ◽  
pp. 781-794 ◽  
Author(s):  
G Martin ◽  
Y Richard
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Organic Compounds ◽  
Heavy Metal Ions ◽  
Laboratory Experiments ◽  
Nitrifying Bacteria ◽  
Inhibitory Effects ◽  
Laboratory Procedure ◽  
Unit Process ◽  
Absorptive Property

Laboratory experiments were conducted on ammonia bio-oxidation to nitrates by mixed cultures of nitrifiers in order to quantify the influence of mineral and organic pollutants on biokinetics parameters. First, the inhibitory effects of various heavy metal ions were studied using laboratory scale activated sludge and submerged filter units. Depending on the unit process and the metal involved, inhibitory effects are observed at concentrations above 1 mg/l. Results obtained provide further support for an hypothesis suggested as an explanation of the toxicity of compounds such as heavy metals: this is based on a Freunclich's adsorption law of heavy metals on nitrifying sludge. No change of inhibitory effects are obtained using fixed films in submerged filters. The effects of organic compounds were examined using the same laboratory procedure. Inhibitory effects of organic compounds in submerged filters depend on their absorptive property. Each of the organic compounds involved may affect nitrifying bacteria.

scholarly journals The simultaneous removal of heavy metals and organic contaminants over a Bi2WO6/mesoporous TiO2 nanotube composite photocatalyst

RSC Advances ◽  
2020 ◽  
Vol 10 (36) ◽  
pp. 21228-21237
Author(s):  
Lei Cheng ◽  
Sijia Liu ◽  
Guangying He ◽  
Yun Hu
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Organic Contaminants ◽  
Dibutyl Phthalate ◽  
Mesoporous Tio2 ◽  
Contaminated Water ◽  
Simultaneous Removal ◽  
Composite Photocatalyst ◽  
Removal Of Heavy Metals ◽  
Nanotube Composites

In this study, Bi2WO6/mesoporous TiO2 nanotube composites (BWO/TNTs) were successfully synthesized to remove the heavy metal Cr(vi) and refractory organic compound dibutyl phthalate (DBP) from contaminated water under visible light.

Study on the adsorption of bacteria in ceramsite and their synergetic effect on adsorption of heavy metals

2013 ◽  
Vol 69 (2) ◽  
pp. 407-413 ◽  
Author(s):  
Shan Qiu ◽  
Fang Ma ◽  
Xu Huang ◽  
Shanwen Xu
Keyword(s):  
Electron Microscopy ◽  
Heavy Metals ◽  
Heavy Metal ◽  
Scanning Electron Microscopy ◽  
Adsorption Capacity ◽  
Synergetic Effect ◽  
Covalent Bond ◽  
Metal Adsorption ◽  
Heavy Metal Adsorption ◽  
Scanning Electron

In this paper, heavy metal adsorption by ceramsite with or without Bacillus subtilis (B. subtilis) immobilization was studied, and the synergetic effect of ceramsite and bacteria was discussed in detail. To investigate the roles of the micro-pore structure of ceramsite and bacteria in removing heavy metals, the amount of bacteria immobilized on the ceramsite was determined and the effect of pH was evaluated. It was found that the immobilization of B. subtilis on the ceramsite was attributed to the electrostatic attraction and covalent bond. The scanning electron microscopy results revealed that, with the presence of ceramsite, there was the conglutination of B. subtilis cells due to the cell outer membrane dissolving. In addition, the B. subtilis immobilized ceramsite showed a different adsorption capacity for different heavy metals, with the adsorption capacity ranking of La3+ &gt; Cu2+ &gt; Mg2+ &gt; Na+.

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