Using ZnO Nanorods Coated Porous Ceramic Monolith to Remove Arsenic from Groundwater

2017 ◽  
Vol 751 ◽  
pp. 756-765 ◽  
Author(s):  
Kannika Khwamsawat ◽  
Jukkrit Mahujchariyawong ◽  
Supamas Danwittayakul
Keyword(s):  
Water Sample ◽  
Arsenic Removal ◽  
Porous Ceramic ◽  
Zno Nanorods ◽  
Arsenic Concentration ◽  
Solution Concentration ◽  
Growth Time ◽  
Arsenic Content ◽  
Growth Solution ◽  
Nano Adsorbent

Arsenic contaminants in drinking water pose a threat to human health. In this study, we report the use of nanotechnology to enhance the efficiency of arsenic removal. In here, zinc oxide (ZnO) has been selected for this application due to its environmentally friendly to human being. One-dimensional ZnO nanorods were grown on porous ceramic substrate by hydrothermal technique. The monolith nano-adsorbents were investigated using field emission scanning electron microscope (FESEM, Hitachi, SE-8030), while phase compositions and specific surface area were examined by x-ray diffractometer (XRD, PAnalitical, X’Pert PRO). Experiments of arsenic adsorption were conducted by using 200 ppb arsenic concentration solution with a continuously stirring system. After the adsorption, each water sample was then measured the arsenic content by inductively coupled plasma-optical emission spectroscope (ICP-OES) as compare to the original water sample to calculate the percentage of arsenic removal. We found that morphology of nano-adsorbent on using the growth solution concentration of 20mM of growth solution concentration and 20 hours of growth time showed the highest density of ZnO hexagonal nanorods with about 100 nm in diameter. The optimization studies obtained 30 minute of adsorption time, pH as 7. This nano-adsorbent exhibited about 98% of arsenic removal. For the comparison with commercial adsorbent (As600), ZnO nano-adsorbent has a better efficiency. The strong competitive ion on the arsenic removal was PO43-. Moreover, the real groundwater after treatment doesn’t have any toxic residue. Therefore, ZnO nanorods coated on porous ceramic can be the candidate material for arsenic removal from groundwater.

As(III) Removal by Dynamic Adsorption onto Amberlite XAD7 Functionalized with Crown Ether and Doped with Fe(III) Ions

2019 ◽  
Vol 70 (7) ◽  
pp. 2330-2334
Author(s):  
Mihaela Ciopec ◽  
Adina Negrea ◽  
Narcis Duteanu ◽  
Corneliu Mircea Davidescu ◽  
Iosif Hulka ◽  
...  
Keyword(s):  
Adsorption Process ◽  
Arsenic Removal ◽  
Arsenic Concentration ◽  
Fixed Bed ◽  
World Health ◽  
Arsenic Content ◽  
Arsenic Adsorption ◽  
Stage Of Development ◽  
Wide Range ◽  
Health Organization

Arsenic content in groundwater�s present a wide range of concentration, ranging from hundreds of micrograms to thousands of micrograms of arsenic per litter, while the maximum permitted arsenic concentration established by World Health Organization (WHO) is 10 mg L-1. According to the WHO all people, regardless of their stage of development and their social economic condition, have the right to have access to adequate drinking water. The most efficient and economic technique used for arsenic removal is represented by adsorption. In order to make this remediation technique more affordable and environmentally friendly is important to new materials with advance adsorbent properties. Novelty of present paper is represented by the usage of a new adsorbent material obtained by physical - chemical modification of Amberlite XAD polymers using crown ethers followed by iron doping, due to well-known affinity of arsenic for iron ions. Present paper aims to test the obtained modified Amberlite polymer for arsenic removal from real groundwater by using adsorption in a fixed bed column, establishing in this way a mechanism for the adsorption process. During experimental work was studied the influence of competing ions from real water into the arsenic adsorption process.

Study on Arsenic Removal in the Simulating Constructed Wetland

2013 ◽  
Vol 777 ◽  
pp. 386-389
Author(s):  
Jun Ying Zhao ◽  
Hua Ming Guo
Keyword(s):  
Constructed Wetland ◽  
Arsenic Removal ◽  
Early Stage ◽  
Arsenic Concentration ◽  
Pteris Vittata ◽  
Small Scale ◽  
Arsenic Content ◽  
Main Role ◽  
Batch Tests ◽  
Concentration Changes

Arsenic concentration changes in small-scale simulating constructed wetland composed with shale ceramic, zeolite, quartz sand andPteris vittatawere examined. During arsenic removal by the constructed wetlands, arsenic interception by the natural media played the main role in the early stage andPteris vittatauptake played the key role for arsenic removal in the later stable stage. When As (III) concentration in inflow was about 1 mg/L, the arsenic removal ratio by the two was between 22.2% and 66.6% and kept about 33% in the end. Arsenic average content in fronds and roots ofPteris vittataafter experiments were respectively 17610 and 2491 mg/kg. Transfer factor was 7.08. Compared with batch tests, arsenic content accumulated in plants increased significantly.

Arsenic Removal by Precipitation with Calcium Phosphate Hydroxyapatite

2012 ◽  
Vol 506 ◽  
pp. 413-416 ◽  
Author(s):  
W. Dungkaew ◽  
K.J. Haller ◽  
A.E. Flood ◽  
J.F. Scamehorn
Keyword(s):  
Calcium Phosphate ◽  
Water Sample ◽  
Removal Efficiency ◽  
Arsenic Removal ◽  
Arsenic Speciation ◽  
Arsenic Concentration ◽  
Contaminated Water ◽  
Low Levels ◽  
Removal Of Arsenic ◽  
Key Parameter

The removal of arsenic from synthetic arsenic contaminated water sample by precipitating arsenic (in the form of arsenate oxyanion) with calcium phosphate hydroxyapatite, HAp, was studied under conditions that induce arsenate incorporated calcium phosphate hydroxyapatite, Ca (P/As)HAp, to form. Arsenate is able to substitute for a fraction of the phosphate in HAp host material as it forms. Consequently, arsenic is successfully removed from the contaminated water achieving up to 99% arsenic removal from 25 ppm initial arsenic concentration. The Ca:(P+As) and P:As mole ratios were found to play an important role in arsenic removal efficiency. Higher Ca:(P+As) and P:As mole ratios give higher arsenic removal efficiency. Surprisingly, the pH of the initial anion solution, a key parameter in arsenic speciation, was found to not have a significant effect on arsenic removal by this process. The advantage of this process is that the precipitation can occur rapidly at relatively low levels of arsenic contamination, implying an easy and inexpensive process for arsenic removal can be developed based on this approach.

scholarly journals Evaluation of Fe-Mg Binary Oxide for As (III) Adsorption—Synthesis, Characterization and Kinetic Modelling

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 805
Author(s):  
Saif Ullah Khan ◽  
Rumman Zaidi ◽  
Feroz Shaik ◽  
Izharul Haq Farooqi ◽  
Ameer Azam ◽  
...  
Keyword(s):  
Arsenic Removal ◽  
Kinetic Modelling ◽  
Arsenic Concentration ◽  
Experimental Studies ◽  
Precipitation Method ◽  
Arsenic Adsorption ◽  
Adsorbent Dosage ◽  
X Ray ◽  
Co Precipitation ◽  
Contaminated Waters

Nanotechnology has received much attention in treating contaminated waters. In the present study, a facile co-precipitation method was employed to synthesize a novel iron and magnesium based binary metal oxide using a stoichiometrically fixed amount of FeNO3.9H2O and MgNO3.6H2O in a proportion of molar concentration 1:1 and was later evaluated in removing As (III) from contaminated waters. Characterization of the prepared nanomaterial was done using X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy Dispersive X-Ray Analysis (EDAX) and ultraviolet–visible spectrophotometry (UV-VIS). Experimental studies on batch scale were carried out, examining the effect of varying initial concentrations of metal, adsorbent dosage, application time and initial pH on removal efficiency. Arsenic removal increased on increasing adsorbent dosage (0.1–1 g/L) but trend reversed on increasing initial arsenic concentration attaining qmax of 263.20 mg/g. Adsorption was quite efficient in pH range 4–8. Freundlich fitted better for adsorption isotherm along with following Pseudo-2nd order kinetics. The reusability and effect of co-existing ions on arsenic adsorption, namely SO42−, CO32− and PO43− were also explored with reusability in 1st and 2nd cycles attained adsorptive removal up to 77% and 64% respectively. The prepared nano-adsorbent showed promising results in terms of high arsenic uptake (qmax of 263.20 mg/g) along with facile and cost-effective synthesis. Thus, the co-precipitation technique used in this work is a simple one step procedure without any use of any precursor as compared to most of the other procedures used for synthesis.

EFFECT OF PRE-HEATING AND SEED LAYER ON HYDROTHERMAL GROWTH AND OPTICAL PROPERTIES OF ZINC OXIDE NANORODS

2011 ◽  
Vol 10 (04n05) ◽  
pp. 845-849
Author(s):  
GAURAV SHUKLA ◽  
ALIKA KHARE
Keyword(s):  
Optical Properties ◽  
Seed Layer ◽  
Zno Nanorods ◽  
Pulsed Laser ◽  
Heating Time ◽  
Hydrothermal Growth ◽  
Zinc Oxide Nanorods ◽  
Growth Time ◽  
Oxide Nanorods ◽  
Reported Effect

Hydrothermal growth of highly c-axis oriented ZnO nanorods with high aspect ratio on pulsed laser deposited ZnO seed layer is reported. Effect of pre-heating time, growth time and seed layer on the structural, morphological and optical properties of ZnO nanorods is presented. The possible growth mechanism for ZnO nanorods is also discussed.

scholarly journals Transfer of Arsenic from Groundwater and Paddy Soil to Rice (Oryza sativa L.) Grain: A Micro Level Study in Chandina, Comilla

2015 ◽  
Vol 12 (2) ◽  
pp. 74-82 ◽  
Author(s):  
Md. Habibur Rahman ◽  
Md. Mohashin Farazi ◽  
Kohinoor Begum ◽  
Md. Serazul Islam
Keyword(s):  
Oryza Sativa ◽  
Irrigation Water ◽  
Agricultural Soil ◽  
Oryza Sativa L ◽  
Arsenic Concentration ◽  
Dry Weight ◽  
Permissible Limit ◽  
Arsenic Content ◽  
Soil Arsenic ◽  
Micro Level

Rice (Oryza sativa L.) is one of the major food crops in many countries. As the cultivation of rice requires huge volume of water, long term use of Arsenic contaminated groundwater for irrigation may result in the increase of arsenic concentration in the agricultural soil and eventually accumulation in rice grains. A micro level study was conducted to investigate the transfer of arsenic from irrigation water and soil to rice plants in the arsenic affected 8 unions of Chandina upazilla, Comilla district. The level of arsenic in irrigation water (0.12±0.08 and 0.67±0.07 mg l-1) was much above the WHO permissible limit of 0.01 mg l-1 for drinking water and FAO permissible limit of 0.10 mg l-1 for irrigation water. The total soil arsenic concentrations ranged from 3.21±0.80 to 8.74±2.83 mg kg-1 dry weight of soil, which was below the maximum acceptable limit for agricultural soil of 20.0 mg kg-1 as recommended by the European Community. The accumulation of arsenic in the grain ranged from 0.12±0.04 to 0.58±0.06 mg kg-1 in Boro and 0.16±0.04 to 1.06±0.20 mg kg-1 in T. Aman. Except grain sample (T. Aman) of one union, the grains in both Boro and T. Aman of all unions did not exceed 1.0 mg kg-1 dry weight of arsenic (the permissible limit of arsenic in rice according to WHO recommendation). Thus, till now rice has remained harmless for consumption in the study area. The results clearly showed that the arsenic content in the grains of Boro rice is correlated to the intensity of arsenic contamination of irrigation water and soil. The Agriculturists 2014; 12(2) 74-82

Causes and distribution of arsenic contamination in Bangladesh: evidence from the literature

Water Policy ◽  
2009 ◽  
Vol 11 (3) ◽  
pp. 362-378 ◽  
Author(s):  
N. Nahar
Keyword(s):  
Water Policy ◽  
Human Error ◽  
New Technology ◽  
Pyrite Oxidation ◽  
Arsenic Concentration ◽  
Leafy Vegetables ◽  
Arsenic Content ◽  
Precautionary Measure ◽  
Arsenic In Groundwater ◽  
Tube Wells

In attempting to eliminate disease caused by drinking polluted surface water, millions of tube-wells were drilled in Bangladesh. However, owing to arsenic in groundwater, the availability of safe drinking water has declined from earlier achievement of 97% to 51.2%. This article reviews the causes and distribution of arsenic concentration in rural Bangladesh from a wide variety of literature. Scientists have converged to two hypotheses for causes of arsenic in groundwater: the pyrite oxidation hypothesis and the oxy-hydroxide reduction hypothesis. There is a positive correlation between arsenic content in irrigated groundwater and arsenic contained in soils. There is a significant presence of arsenic in rice and leafy vegetables. Today, arsenic is causing toxicity to human health and creating major social problems. This finding implies that, had there been a precautionary measure taken when a new technology tube-well was being introduced, in the form of testing water for harmful metals, the risk that the rural population is facing now could have been drastically reduced. This lack of precautionary measure, before starting a mass installation of tube-wells for drinking and irrigation should be seen as a “human error” and avoided in future water policy and planning.

Arsenic removal by ferric-chloride coagulation – effect of phosphate, bicarbonate and silicate

2011 ◽  
Vol 64 (5) ◽  
pp. 1046-1055 ◽  
Author(s):  
Dóra Laky ◽  
István Licskó
Keyword(s):  
Adverse Effect ◽  
Arsenic Removal ◽  
Linear Regression Analysis ◽  
Arsenic Concentration ◽  
Ferric Hydroxide ◽  
Multiple Linear Regression Analysis ◽  
Ph Values ◽  
Robust Model ◽  
Coagulant Dosage ◽  
Negative Effect

Jar tests with synthetic water were carried out in order to investigate the effect of phosphate, bicarbonate and silicate on arsenic removal efficiency by in-situ formed ferric hydroxide. Above 12 mg C/L inorganic carbon concentration, the adverse effect of bicarbonate was definite, and resulted in higher remaining arsenic concentration. At all pH values (7.5–7.8) and coagulant dosages (0.84–3.00 mg/L Fe) tested, the negative effect of phosphate on arsenic removal was also evident. In the presence of silicate small ferric-hydroxide colloids were formed, which were able to go through the 0.45 μm pore-size membrane. Compared to silicate-free systems, 2.5–3.5 times higher coagulant dose was needed to achieve the target arsenic concentration in the presence of 14–23 mg/L Si. At higher pH values the adverse effect of silicate was even more significant. All data were merged and multiple linear regression analysis was carried out in order to build up a robust model to predict the residual arsenic concentration if the raw water contains 50–60 μg/L initial arsenic concentration. The estimation was based on the following variables: PO4-P concentration, final pH, Si concentration, Fe(III) dose. The most important influencing factors proved to be the silicate concentration and applied coagulant dosage.

Pilot-Scale Performance of Iron and Arsenic Removal from Contaminated Groundwater

2005 ◽  
Vol 40 (1) ◽  
pp. 82-90 ◽  
Author(s):  
Biswaranjan Manna ◽  
Uday Chand Ghosh
Keyword(s):  
Arsenic Removal ◽  
Cost Effective ◽  
Pilot Scale ◽  
Cost Evaluation ◽  
Contaminated Groundwater ◽  
Arsenic Content ◽  
Hand Pump ◽  
Excess Iron ◽  
Tube Wells ◽  
Performance Results

Abstract Pilot-scale performance in reducing excess iron and arsenic from contaminated groundwater has been systematically reported. Here, a double column unit, the first packed with β-MnO2 and the second with crystalline FeOOH (goethite variety), with filters attached to the outlet of hand-pump tube-wells has been used in the field. Results showed that the filters generate 10,000 to 15,000 BV and 19,000 to 35,000 BV water with iron ≤ 0.3 mg/L and arsenic ≤10 µg/L from groundwater having influent iron and arsenic levels of 3.75 to 7.25 mg/L and 70 to 220 µg/L, respectively. The downflow rate of effluent water was 237.6 to 305.5 L/m2-min. The performance results were achieved with a single charging of the iron and arsenic removal media. Toxicity characteristic leaching procedure (TCLP) tests of the waste (arsenic content: 2.4 g/kg) showed that it is not hazardous to the environment and does not pose any risk to users. Cost evaluation showed $US0.50 to 0.70 per 1000 gallons of treated water and, hence, the technology is cost-effective for countries such as India and Bangladesh.

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