Synthesis and Characterization of ZnO Nanorods as an Adsorbent for Cr(VI) Sequestration

2019 ◽  
Vol 233 (7) ◽  
pp. 995-1017 ◽  
Author(s):  
Sadia Ata ◽  
Anila Tabassum ◽  
Ismat Bibi ◽  
Samina Ghafoor ◽  
Abdul Ahad ◽  
...  
Keyword(s):  
Zno Nanorods ◽  
Zinc Nitrate ◽  
Nitrate Hexahydrate ◽  
Order Kinetic ◽  
Hydrothermal Route ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Isotherms And Thermodynamics ◽  
Heavy Metals Ions ◽  
Triton X

Abstract Zinc oxide (ZnO) nanorods were fabricated through hydrothermal route and employed for the adsorption of Cr(VI) ions from aqueous medium. Zinc nitrate hexahydrate (Zn(NO3)2.6H2O) was used as a zinc precursor and Triton-x 100 was used as a capping agent. As synthesized ZnO nanorods were characterized by UV-visible spectroscopy (UV), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy dispersive X-Ray spectroscopy (EDX) techniques. The adsorption affecting parameters were investigated for maximum adsorption of Cr(VI) onto ZnO nanorods. The adsorption kinetics, isotherms, and thermodynamics were applied for adsorption mechanism evaluation. Maximum adsorption of Cr(VI) ions (250 mg/g) was achieved using 0.055 g/L ZnO dose at pH 2.0 for the contact time of 30 min. Pseudo-second-order kinetic model and Langmuir isotherm explained well the Cr(VI) adsorption onto ZnO nanorods. The Cr(VI) adsorption onto ZnO was spontaneous and endothermic in nature. In view of promising adsorption efficiency, ZnO nanorods could possibly be used for Cr(VI) ions removal from wastewater and also extendable for the adsorption of other heavy metals ions.

Synthesis of Functionalized Magnetite Titanium Dioxide Nanocomposite for Removal of Acid Fuchsine Dye

2018 ◽  
Vol 21 (8) ◽  
pp. 583-593 ◽  
Author(s):  
Sara Rahnama ◽  
Shahab Shariati ◽  
Faten Divsar
Keyword(s):  
Titanium Dioxide ◽  
Removal Efficiency ◽  
Magnetic Core ◽  
Fractional Factorial ◽  
Order Kinetic ◽  
Sorption Data ◽  
Salt Addition ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Ft Ir

Objective: In this research, a novel magnetite titanium dioxide nanocomposite functionalized by amine groups (Fe3O4@SiO2@TiO2-NH2) was synthesized and its ability for efficient removal of Acid Fuchsine as an anionic dye from aqueous solutions was investigated. Method: The core-shell structure of Fe3O4@SiO2@TiO2 was prepared using Fe3O4 as magnetic core, tetra ethyl orthosilicate as silica and tetra butyl titanate as titanium source for shell. The synthesized nanocomposites (particle size lower than 44 nm) were characterized by FT-IR, XRD, DRS, SEM and TGA instruments. The various experimental parameters affecting dye removal efficiency were investigated and optimized using Taguchi fractional factorial design. Results: The synthesized adsorbent showed the highest removal efficiency of Acid Fuchsine (99 %) at pH= 3.5, without salt addition and during stirring at contact times less than 10 minutes. The study of kinetic models at two concentration levels showed the fast dye sorption on the surface of proposed nanocomposites with pseudo second order kinetic model (R2=1). Also, the fitting of Acid Fuchsine sorption data to Freundlich, Langmuir and Temkin isotherms suggested that Freundlich model gave a better fitting than other models (R2=0.9936, n=2). Conclusion: Good chemical stability, excellent magnetic properties, very fast adsorption kinetics and high removal efficiency make the synthesized nanocomposite as a proper recoverable sorbent for removal of Acid Fuchsine dye from wastewaters.

scholarly journals Development of Biochars Derived from Water Bamboo (Zizania latifolia) Shoot Husks Using Pyrolysis and Ultrasound-Assisted Pyrolysis for the Treatment of Reactive Black 5 (RB5) in Wastewater

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1615
Author(s):  
Thanh Tam Nguyen ◽  
Hung-Hsiang Chen ◽  
Thi Hien To ◽  
Yu-Chen Chang ◽  
Cheng-Kuo Tsai ◽  
...  
Keyword(s):  
Cost Effective ◽  
Reactive Black 5 ◽  
Order Kinetic ◽  
Sem Images ◽  
Zizania Latifolia ◽  
Surface Areas ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Ultrasound Assisted ◽  
Green Technique

Adsorbent made by carbonization of biomass under oxygen-limited conditions has become a promising material for wastewater treatment owing to its cost-effective, simple, and eco-friendly processing method. Ultrasound is considered a green technique to modify carbon materials because it uses water as the solvent. In this study, a comparison of Reactive Black 5 (RB5) adsorption capacity between biochar (BC) generated by pyrolysis of water bamboo (Zizania latifolia) husks at 600 °C and ultrasound-assisted biochar (UBC) produced by pyrolysis at 600 °C assisted by ultrasonic irradiation was performed. UBC showed a greater reaction rate and reached about 80% removal efficiency after 4 h, while it took 24 h for BC to reach that level. Scanning electron microscope (SEM) images indicated that the UBC morphology surface was more porous, with the structure of the combination of denser mesopores enhancing physiochemical properties of UBC. By Brunauer, Emmett, and Teller (BET), the specific surface areas of adsorbent materials were analyzed, and the surface areas of BC and UBC were 56.296 m2/g and 141.213 m2/g, respectively. Moreover, the pore volume of UBC was 0.039 cm3/g, which was higher than that of BC at 0.013 cm3/g. The adsorption isotherms and kinetics revealed the better fits of reactions to Langmuir isotherm and pseudo-second-order kinetic model, indicating the inclination towards monolayer adsorption and chemisorption of RB5 on water bamboo husk-based UBC.

Adsorption Characteristics of Phenol in Aqueous Solution by Pinus massoniana Biochar

2013 ◽  
Vol 295-298 ◽  
pp. 1154-1160 ◽  
Author(s):  
Guo Zhi Deng ◽  
Xue Yuan Wang ◽  
Xian Yang Shi ◽  
Qian Qian Hong
Keyword(s):  
Aqueous Solution ◽  
Ph Value ◽  
Pinus Massoniana ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Adsorbent Dosage ◽  
Salt Ions ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The objective of this paper is to investigate the feasibility of phenol adsorption from aqueous solution by Pinus massoniana biochar. Adsorption conditions, including contact time, initial phenol concentration, adsorbent dosage, strength of salt ions and pH, have been investigated by batch experiments. Equilibrium can be reached in 24 h for phenol from 50 to 250 mg• L-1. The optimum pH value for this kind of biochar is 5.0. The amount of phenol adsorbed per unit decreases with the increase in adsorbent dosage. The existence of salt ions makes negligible influence on the equilibrium adsorption capacity. The experimental data is analyzed by the Freundlich and Langmuir isotherm models. Equilibrium data fits well to the Freundlich model. Adsorption kinetics models are deduced and the pseudo-second-order kinetic model provides a good correlation for the adsorbent process. The results show that the Pinus massoniana biochar can be utilized as an effective adsorption material for the removal of phenol from aqueous solution.

scholarly journals Sawdust for the Removal of Heavy Metals from Water: A Review

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4318
Author(s):  
Elie Meez ◽  
Abbas Rahdar ◽  
George Z. Kyzas
Keyword(s):  
Heavy Metals ◽  
Adsorption Mechanism ◽  
Freundlich Isotherm ◽  
Order Kinetic ◽  
Suitable Material ◽  
Removal Of Heavy Metals ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
And Control ◽  
Environmental Agencies

The threat of the accumulation of heavy metals in wastewater is increasing, due to their abilities to inflict damage to human health, especially in the past decade. The world’s environmental agencies are trying to issue several regulations that allow the management and control of random disposals of heavy metals. Scientific studies have heavily focused on finding suitable materials and techniques for the purification of wastewaters, but most solutions have been rejected due to cost-related issues. Several potential materials for this objective have been found and have been compared to determine the most suitable material for the purification process. Sawdust, among all the materials investigated, shows high potential and very promising results. Sawdust has been shown to have a good structure suitable for water purification processes. Parameters affecting the adsorption mechanism of heavy metals into sawdust have been studied and it has been shown that pH, contact time and several other parameters could play a major role in improving the adsorption process. The adsorption was found to follow the Langmuir or Freundlich isotherm and a pseudo second-order kinetic model, meaning that the type of adsorption was a chemisorption. Sawdust has major advantages to be considered and is one of the most promising materials to solve the wastewater problem.

scholarly journals The sorption of inorganic arsenic on modified sepiolite: Effect of hydrated iron(III)-oxide

2014 ◽  
Vol 79 (7) ◽  
pp. 815-828 ◽  
Author(s):  
Nikola Ilic ◽  
Slavica Lazarevic ◽  
Vladana Rajakovic-Ognjanovic ◽  
Ljubinka Rajakovic ◽  
Djordje Janackovic ◽  
...  
Keyword(s):  
Sorption Capacity ◽  
Arsenic Removal ◽  
Ph Value ◽  
Inorganic Arsenic ◽  
Arsenic Species ◽  
Deionized Water ◽  
Order Kinetic ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The sorption of inorganic arsenic species, As(III) and As(V), from water by sepiolite modified with hydrated iron(III) oxide was investigated at 25 ?C through batch studies. The influence of the initial pH value, the initial As concentrations, the contact time and types of water on the sorption capacity was investigated. Two types of water were used, deionized and groundwater. The maximal sorption capacity for As(III) from deionized water was observed at initial and final pH value 7.0, while the bonding of As(V) was observed to be almost pH independent for pH value in the range from 2.0 to 7.0, and the significant decrease in the sorption capacity was observed at pH values above 7.0. The sorption capacity at initial pH 7.0 was about 10 mg g?1 for As(III) and 4.2 mg g?1 for As(V) in deionized water. The capacity in groundwater was decreased by 40 % for As(III) and by 20 % for As(V). The Langmuir model and pseudo-second order kinetic model revealed good agreement with the experimental results. The results show that Fe(III)-modified sepiolite exhibits significant affinity for arsenic removal and it has a potential for the application in water purification processes.

Phosphorus removal from aqueous solution using a novel granular material developed from building waste

2017 ◽  
Vol 75 (6) ◽  
pp. 1500-1511 ◽  
Author(s):  
Shengjiong Yang ◽  
Pengkang Jin ◽  
Xiaochang C. Wang ◽  
Qionghua Zhang ◽  
Xiaotian Chen
Keyword(s):  
Granular Material ◽  
Chemical Precipitation ◽  
Phosphate Removal ◽  
Precipitation Process ◽  
Order Kinetic ◽  
Solution Ph ◽  
Experimental Conditions ◽  
Removal Capacity ◽  
Order Kinetic Model ◽  
Pseudo Second Order

In this study, a granular material (GM) developed from building waste was used for phosphate removal from phosphorus-containing wastewater. Batch experiments were executed to investigate the phosphate removal capacity of this material. The mechanism of removal proved to be a chemical precipitation process. The characteristics of the material and resulting precipitates, the kinetics of the precipitation and Ca2+ liberation processes, and the effects of dosage and pH were investigated. The phosphate precipitation and Ca2+ liberation processes were both well described by a pseudo-second-order kinetic model. A maximum precipitation capacity of 0.51 ± 0.06 mg g−1 and a liberation capacity of 6.79 ± 0.77 mg g−1 were measured under the experimental conditions. The processes reached equilibrium in 60 min. The initial solution pH strongly affected phosphate removal under extreme conditions (pH <4 and pH >10). The precipitates comprised hydroxyapatite and brushite. This novel GM can be considered a promising material for phosphate removal from wastewater.

Studies of Chromium Removal from Tannery Effluents by Dead Streptomyces Rimosus

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Mohamed Nasser Sahmoune ◽  
Krim Louhab ◽  
Aissa Boukhiar
Keyword(s):  
Fractional Power ◽  
Kinetic Studies ◽  
Second Order ◽  
Order Kinetic ◽  
Streptomyces Rimosus ◽  
Tannery Effluents ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Ph Range

Dead streptomyces rimosus was found to be an effective biosorbent for the removal of chromium from industrial tanning effluents. A sorption level of 65 mg/g was observed at pH 4.8 while the precipitation effect augmented this value at a higher pH range. Chromium desorption increased with decreasing desorption agents pH (including HCl and H2SO4) to a maximum value of 95% at approximately zero pH. The biosorption data of trivalent chromium by streptomyces rimosus has been used for kinetic studies based on fractional power, Elovich, pseudo-first order and pseudo-second order rate expressions. The time-dependent Cr (III) biosorption data were well-described by a pseudo-second-order kinetic model. The intraparticle diffusion is not the rate-limiting step for the whole reaction. It was found that the biosorption equilibrium data fit well with the Langmuir model.

scholarly journals Insights into Starch Coated Nanozero Valent Iron-Graphene Composite for Cr(VI) Removal from Aqueous Medium

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Prasanna Kumarathilaka ◽  
Vimukthi Jayaweera ◽  
Hasintha Wijesekara ◽  
I. R. M. Kottegoda ◽  
S. R. D. Rosa ◽  
...  
Keyword(s):  
Point Of Zero Charge ◽  
Inert Material ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
Graphene Composite ◽  
Removal Capacity ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
First Time

Embedding nanoparticles into an inert material like graphene is a viable option since hybrid materials are more capable than those based on pure nanoparticulates for the removal of toxic pollutants. This study reports for the first time on Cr(VI) removal capacity of novel starch stabilized nanozero valent iron-graphene composite (NZVI-Gn) under different pHs, contact time, and initial concentrations. Starch coated NZVI-Gn composite was developed through borohydrate reduction method. The structure and surface of the composite were characterized by scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), and point of zero charge (pHpzc). The surface area and pHpzc of NZVI-Gn composite were reported as 525 m2 g−1 and 8.5, respectively. Highest Cr(VI) removal was achieved at pH 3, whereas 67.3% was removed within first few minutes and reached its equilibrium within 20 min obeying pseudo-second-order kinetic model, suggesting chemisorption as the rate limiting process. The partitioning of Cr(VI) at equilibrium is perfectly matched with Langmuir isotherm and maximum adsorption capacity of the NZVI-Gn composite is 143.28 mg g−1. Overall, these findings indicated that NZVI-Gn composite could be utilized as an efficient and magnetically separable adsorbent for removal of Cr(VI).

REMOVAL OF STRONTIUM (II) FROM AQUEOUS SOLUTION USING FUNCTIONALIZED CARBON NANOTUBES

2012 ◽  
Vol 11 (02) ◽  
pp. 1250019 ◽  
Author(s):  
RAJESH KUMAR ◽  
S. K. JAIN
Keyword(s):  
Carbon Nanotubes ◽  
Polluted Water ◽  
Order Kinetic ◽  
Environmental Application ◽  
Functionalized Carbon Nanotubes ◽  
Multi Wall Carbon Nanotubes ◽  
Adsorption Data ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Ft Ir

This study was carried out to evaluate the environmental application of functionalized carbon nanotubes through the experimental removal of strontium (II) from water. The aim was to find the optimal condition for the removal of strontium from water under different conditions such as initial concentration of strontium, contact time and neutral pH. The functionalized multi wall carbon nanotubes (f-MWCNT) were characterized by FT-IR and scanning electron microscopy (SEM). The adsorption isotherms were correlated to Freundlich and Langmuir models and it was found that the adsorption data could be fitted better by Langmuir model than Freundlich one. The kinetic data shows that the adsorption describes well with the pseudo-second order kinetic model. Functionalized MWCNT can be used as good adsorbent for the removal of the strontium ions from polluted water according to results.

Effects of tall fescue biochar on the adsorption behavior of desethyl-atrazine in different types of soil

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 3575-3595
Author(s):  
Wanting Li ◽  
Ruifeng Shan ◽  
Yuna Fan ◽  
Xiaoyin Sun
Keyword(s):  
Tall Fescue ◽  
Adsorption Process ◽  
Exothermic Reaction ◽  
Equilibrium Concentration ◽  
Black Soil ◽  
Adsorption Behavior ◽  
Order Kinetic ◽  
Isothermal Adsorption ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Desethyl-atrazine (DEA) is a metabolite of atrazine that exerts a considerable influence on the environment. In this study, tall fescue biochar was prepared by pyrolysis at 500 °C, and batch experiments were conducted to explore its effect on the adsorption behavior of DEA in red soil, brown soil, and black soil. The addition of biochar increased the equilibrium amount of DEA adsorption for the three soil types. A pseudo-second-order kinetic model most closely fit the DEA adsorption kinetics of the three soils with and without biochar, with a determination coefficient (R2) of 0.962 to 0.999. The isothermal DEA adsorption process of soils with and without biochar was optimally described by the Freundlich and Langmuir isothermal adsorption models with R2 values of 0.98 and above. The DEA adsorption process in the pristine soil involved an exothermic reaction, which became an endothermic reaction after the addition of biochar. Partitioning was dominant throughout the entire DEA adsorption process of the three pristine soils. Conversely, in soils with biochar, surface adsorption represented a greater contribution toward DEA adsorption under conditions of low equilibrium concentration. The overall results revealed that the tall fescue biochar was an effective adsorbent for DEA polluted soil.

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