scholarly journals Enriching Trace Level Adsorption Affinity of As3+ Ion Using Hydrothermally Synthesized Iron-Doped Hydroxyapatite Nanorods

2021 ◽  
Author(s):  
Sandeep Eswaran Panchu ◽  
Saranya Sekar ◽  
Vani Rajaram ◽  
Elayaraja Kolanthai ◽  
Sarojini Jeeva Panchu ◽  
...  
Keyword(s):  
Trace Level ◽  
Adsorption Affinity ◽  
Iron Doped

Enriching Trace Level Adsorption Affinity of As3+ ion using Hydrothermally Synthesized Iron-Doped Hydroxyapatite Nanorods

2021 ◽  
Author(s):  
Sandeep Eswaran Panchu ◽  
Saranya Sekar ◽  
Vani Rajaram ◽  
Elayaraja Kolanthai ◽  
Sarojini Jeeva Panchu ◽  
...  
Keyword(s):  
Colloidal Stability ◽  
Low Cost ◽  
Maximum Adsorption Capacity ◽  
Drastic Reduction ◽  
Efficient Removal ◽  
Trace Level ◽  
Adsorption Affinity ◽  
Monolayer Adsorption ◽  
Iron Doped ◽  
Efficient Adsorbent

Abstract Contamination of arsenic in the form of arsenite (As3+) and arsenate (As5+) in potable water causes serious illness in the human body even at a very low concentration (10 µg / L). As3+ is comparatively 60 times more toxic than As5+ species. Hence, this work is focused on the preparation of adsorbents for efficient removal of As3+ with higher adsorption affinity at trace level (≤50 µg/L). Here, iron-doped hydroxyapatite (Fe-HAp) synthesized by hydrothermal technique is employed as an efficient adsorbent. A very less quantity of Fe2+ ion (0.5 wt %) is incorporated in the tetrahedral and octahedral sites of the HAp lattice along the c-axis which lead to drastic reduction in particle size (400%) and enhancing the specific surface area (105%), colloidal stability, and adsorption affinity. The maximum adsorption capacity of As3+ is 139±2 µg/g and 183±2 µg/g for HAp and Fe-HAp, respectively. The adsorption rate of Fe-HAp is very rapid which is 538% higher compared to HAp and also the As3+ adsorption affinity or sensitivity (0.71 µg/L) significantly improved 83-99% when compared to the adsorbents reported in the previous literature so far. The monolayer adsorption of As3+ is purely strong chemisorption as confirmed by the Langmuir and Dubinin–Radushkevich (DKR) isotherm. The structure and morphology of HAp and Fe-HAp remain unchanged after the adsorption of As3+ ions and also no secondary toxic products were observed. Hence, the above results reveal Fe-HAp as an efficient and low-cost adsorbent for removal of highly toxic As3+ ions at the trace level.

Analysis of Trace Level Perchlorate in Drinking Water and Ground Water by Electrospray Mass Spectrometry

1998 ◽  
Author(s):  
Rebecca A. Clewell ◽  
Wayne T. Brashear ◽  
David T. Tsui ◽  
Sanwat Chaudhuri ◽  
Rachel S. Cassady
Keyword(s):  
Mass Spectrometry ◽  
Drinking Water ◽  
Ground Water ◽  
Electrospray Mass Spectrometry ◽  
Trace Level

scholarly journals Development of a simplified gas ultracleaning process: experiments in biomass residue-based fixed-bed gasification syngas

2021 ◽  
Author(s):  
Christian Frilund ◽  
Esa Kurkela ◽  
Ilkka Hiltunen
Keyword(s):  
Activated Carbons ◽  
Low Cost ◽  
Fixed Bed ◽  
Carbonyl Sulfide ◽  
Gas Analysis ◽  
Small Scale ◽  
Cleaning Process ◽  
Medium Temperature ◽  
Gas Cleaning ◽  
Adsorption Affinity

AbstractFor the realization of small-scale biomass-to-liquid (BTL) processes, low-cost syngas cleaning remains a major obstacle, and for this reason a simplified gas ultracleaning process is being developed. In this study, a low- to medium-temperature final gas cleaning process based on adsorption and organic solvent-free scrubbing methods was coupled to a pilot-scale staged fixed-bed gasification facility including hot filtration and catalytic reforming steps for extended duration gas cleaning tests for the generation of ultraclean syngas. The final gas cleaning process purified syngas from woody and agricultural biomass origin to a degree suitable for catalytic synthesis. The gas contained up to 3000 ppm of ammonia, 1300 ppm of benzene, 200 ppm of hydrogen sulfide, 10 ppm of carbonyl sulfide, and 5 ppm of hydrogen cyanide. Post-run characterization displayed that the accumulation of impurities on the Cu-based deoxygenation catalyst (TOS 105 h) did not occur, demonstrating that effective main impurity removal was achieved in the first two steps: acidic water scrubbing (AWC) and adsorption by activated carbons (AR). In the final test campaign, a comprehensive multipoint gas analysis confirmed that ammonia was fully removed by the scrubbing step, and benzene and H2S were fully removed by the subsequent activated carbon beds. The activated carbons achieved > 90% removal of up to 100 ppm of COS and 5 ppm of HCN in the syngas. These results provide insights into the adsorption affinity of activated carbons in a complex impurity matrix, which would be arduous to replicate in laboratory conditions.

Anatase porous titania nanosheets for resonant-gravimetric detection of ppb-level NO2 at room-temperature

The Analyst ◽  
2021 ◽  
Author(s):  
Jialin Yang ◽  
Ding Wang ◽  
Ming Li ◽  
Haitao Yu ◽  
Pengcheng Xu ◽  
...  
Keyword(s):  
Public Health ◽  
Environmental Protection ◽  
Room Temperature ◽  
Trace Level ◽  
Porous Titania

The trace-level detection to harmful NO2 gas at room-temperature is very important for environmental protection and public health. This paper reports the resonant-gravimetric detection of ppb-level NO2 at room-temperature using...

Mercury speciation at trace level using fluorescein hydrazide as fluorescent probe

2021 ◽  
Author(s):  
Kempahanumakkagaari Sureshkumar ◽  
Thippeswamy Ramakrishnappa ◽  
Malingappa Pandurangappa
Keyword(s):  
Fluorescent Probe ◽  
Mercury Speciation ◽  
Trace Level

scholarly journals Adsorption and Desorption Mechanisms of Rare Earth Elements (REEs) by Layered Double Hydroxide (LDH) Modified with Chelating Agents

2019 ◽  
Vol 9 (22) ◽  
pp. 4805 ◽  
Author(s):  
Shuang Zhang ◽  
Naoki Kano ◽  
Kenji Mishima ◽  
Hirokazu Okawa
Keyword(s):  
Rare Earth ◽  
Quantum Chemistry ◽  
Rare Earth Elements ◽  
Adsorption Capacity ◽  
Density Functional ◽  
Stable State ◽  
Experimental Result ◽  
Adsorption And Desorption ◽  
Adsorption Affinity ◽  
Quantum Chemistry Calculations

In order to obtain the adsorption mechanism and adsorption structures of Rare Earth Elements (REEs) ions adsorbed onto layered double hydroxides (LDH), the adsorption performance of LDH and ethylenediaminetetraacetic acid (EDTA) intercalated LDH for REEs was investigated by batch experiments and regeneration studies. In addition to adsorption capacity, the partition coefficient (PC) was also evaluated to assess their true performance metrics. The adsorption capacity of LDH increases from 24.9 μg·g−1 to 145 μg·g−1 for Eu, and from 20.8 μg·g−1 to 124 μg·g−1 for La by intercalating EDTA in this work; and PC increases from 45.5 μg·g−1·uM−1 to 834 μg·g−1·uM−1 for Eu, and from 33.6 μg·g−1·μM−1 to 405 μg·g−1·μM−1 for La. Comparison of the data indicates that the adsorption affinity of EDTA-intercalated LDH is better than that of precursor LDH no matter whether the concept of adsorption capacity or that of the PC was used. The prepared adsorbent was characterized by XRD, SEM-EDS and FT-IR techniques. Moreover, quantum chemistry calculations were also performed using the GAUSSIAN09 program package. In this calculation, the molecular locally stable state structures were optimized by density functional theory (DFT). Both the quantum chemistry calculations and the experimental data showed that REEs ions adsorbed by EDTA-intercalated LDH are more stable than those adsorbed by precursor LDH. Furthermore, the calculation results of adsorption and desorption rates show that adsorption rates are larger for Eu(III) than for La(III), which agrees with the experimental result that Eu(III) has a higher adsorption ability under the same conditions. The LDHs synthesized in this work have a high affinity for removing REEs ions.

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