scholarly journals Effects of Calcination Temperature and Chemical Modification on the Adsorption of Cd and As(V) by Biochar Derived from Pteris Vittata

2021 ◽  
Author(s):  
Kazuki Sugawara ◽  
Kouhei Ichio ◽  
Yumiko Ichikawa ◽  
Hitoshi Ogawa ◽  
Seiichi Suzuki
Keyword(s):  
Chemical Modification ◽  
Adsorption Capacity ◽  
Toxic Elements ◽  
Plant Biomass ◽  
Pteris Vittata ◽  
Adsorption Capacities ◽  
Biomass Resources ◽  
As Adsorption ◽  
Effective Use ◽  
Very High

Abstract Phytoremediation can be applied successfully to solve the serious worldwide issue of arsenic (As) and cadmium (Cd) pollution. However, the treatment of biomass containing toxic elements after remediation is a challenge. In this study, we investigated the effective use of biomass resources by converting the As hyperaccumulator P. vittata into biochar to adsorb toxic elements. Plant biomass containing As was calcined at 600 °C, 800 °C, and 1200 °C and its surface structure and adsorption performances for As and Cd were evaluated. Calcination at 1200 °C increased the specific surface area of the biochar, but it did not significantly affect its adsorption capacity for toxic elements. The calcined biochar had very high adsorption capacities of 90% and 95% for As and Cd, respectively, adsorbing 450 mg/g-biochar of both elements. The As adsorption rate was improved by FeCl3 treatment. However, the adsorption capacity for Cd was not significantly affected by the NaOH treatment. In conclusion, it was found that after phytoremediation using P. vittata biomass, it can be effectively used as an environmental purification material by conversion to biochar. Furthermore, chemical modification with FeCl3 improves the biochar’s adsorption performance.

scholarly journals ELIMINATION OF TOXIC ELEMENTS BY NATURAL AND SYNTHETIC ADSORBENTS

2020 ◽  
Vol 1 (21) ◽  
Author(s):  
Zuzana Danková ◽  
Alexandra Bekényiová ◽  
Zuzana Mitróová ◽  
Danka Gešperová
Keyword(s):  
Chemical Modification ◽  
Adsorption Capacity ◽  
Quartz Sand ◽  
Toxic Elements ◽  
Magnetic Particles ◽  
Binary Solution ◽  
Adsorption Properties ◽  
Column Tests ◽  
Batch Tests ◽  
Synthetic Adsorbents

The adsorption of Zn(II) and Cu(II) onto siderite (S) and kaolin (K) and adsorption of As(V) ontobentonite (B) was studied. The chemical modification – precipitation of MnO2 on the kaolin (KM) andsiderite (SM) surface was used to improve the adsorption properties of natural materials for theirapplication in columns. In the batch tests the higher adsorption capacity was observed for the KMsample. The binary solution of Zn(II)/Cu(II) was percolated through the columns filled with quartz sand(QS) as a bearer of KM or SM. The effect of toxic elements removal reached in average 90 % for bothcolumns.The adsorption of As(V) onto natural bentonite (B) and synthetic magnetic particles (MP) was studiedby batch as well as column tests. Whereas the B sample did not perform good adsorption properties inbatch test, in dynamic conditions its effect was comparable with MP. The effect of As(V) removal wasstudied in a number of series with different materials beddings and cycles repetitions. The resultsshowed that the most effective was the column filled with QS+B+MP containing more coarse-grainedfraction of bentonite. In the second cycle its removal effect reached 60 % of As(V) elimination from thesolution.

scholarly journals Phosphate has a differential influence on arsenate adsorption by soils with different properties

2012 ◽  
Vol 58 (No. 9) ◽  
pp. 405-411 ◽  
Author(s):  
X. Zeng ◽  
P. Wu ◽  
S. Su ◽  
L. Bai ◽  
Q. Feng
Keyword(s):  
Adsorption Capacity ◽  
Agricultural Soils ◽  
Molar Ratio ◽  
Adsorption Sites ◽  
Adsorption Capacities ◽  
Minimum Capacity ◽  
P Application ◽  
As Adsorption ◽  
Langmuir And Freundlich Equations ◽  
Different Soils

The adverse effect of the application of phosphorus (P) on arsenic (As) adsorption by soils can result in increasing mobility and availability of As. However, in different soils, P might influence As adsorption differently. In this study, the arsenate [As<sup>(V)</sup>] adsorption capacities of six soils with different properties and the effects of P application were studied. The results indicated that the adsorbed As<sup>(V)</sup> contents all increased as a function of the As<sup>(V)</sup> content in equilibrium. When analysed using the Langmuir and Freundlich equations, the maximum As<sup>(V)</sup> adsorption capacity of 0.72 mg/g was found for an Alumi-Plinthic Acrisol, while the minimum capacity of 0.09 mg/g was observed for an Epigleyic Cambisol. The adverse effects of P application on As<sup>(V)</sup> adsorption by the six soils were observed to be variable. When the P/As molar ratio in a culture experiment was increased from 0 to 10, the maximal and minimal decreases in the As<sup>(V)</sup> adsorption capacity of 0.086 and 0.014 mg/g were found in the Alumi-Plinthic Acrisol and Epigleyic Cambisol, respectively. P was relatively more effective in competing for adsorption sites with As<sup>(V)</sup> in the Alumi-Plinthic Acrisol and Luvi-Endogleyic Phaeozem due to their higher A/P values (decrease in adsorbed<br />As/added P) of 1.143 and 1.135, respectively. These results will help decrease the environmental risk of some As-contaminated agricultural soils through the controlled application of P.

scholarly journals Rapid Water Softening with TEMPO-Oxidized/Phosphorylated Nanopapers

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 136 ◽  
Author(s):  
Andreas Mautner ◽  
Thawanrat Kobkeatthawin ◽  
Florian Mayer ◽  
Christof Plessl ◽  
Selestina Gorgieva ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Cellulose Nanofibrils ◽  
Water Hardness ◽  
Organic Liquids ◽  
Oxidized Cellulose ◽  
Water Softening ◽  
Aqueous Suspensions ◽  
Overall Performance ◽  
Exchange Resins ◽  
Very High

Water hardness not only constitutes a significant hazard for the functionality of water infrastructure but is also associated with health concerns. Commonly, water hardness is tackled with synthetic ion-exchange resins or membranes that have the drawbacks of requiring the awkward disposal of saturated materials and being based on fossil resources. In this work, we present a renewable nanopaper for the purpose of water softening prepared from phosphorylated TEMPO-oxidized cellulose nanofibrils (PT-CNF). Nanopapers were prepared from CNF suspensions in water (PT-CNF nanopapers) or low surface tension organic liquids (ethanol), named EPT-CNF nanopapers, respectively. Nanopaper preparation from ethanol resulted in a significantly increased porosity of the nanopapers enabling much higher permeances: more than 10,000× higher as compared to nanopapers from aqueous suspensions. The adsorption capacity for Ca2+ of nanopapers from aqueous suspensions was 17 mg g−1 and 5 mg g−1 for Mg2+; however, EPT-CNF nanopapers adsorbed more than 90 mg g−1 Ca2+ and almost 70 mg g−1 Mg2+. The higher adsorption capacity was a result of the increased accessibility of functional groups in the bulk of the nanopapers caused by the higher porosity of nanopapers prepared from ethanol. The combination of very high permeance and adsorption capacity constitutes a high overall performance of these nanopapers in water softening applications.

scholarly journals Enhancement of the Congo Red Adsorption Capacity of Biochars by Surface Modification with MgCl2 Pretreatment

2020 ◽  
Vol 42 (10) ◽  
pp. 472-481
Author(s):  
Hee So Oh ◽  
Jae-Soo Chang
Keyword(s):  
Surface Modification ◽  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Congo Red ◽  
Raw Materials ◽  
Physicochemical Characteristics ◽  
Pine Sawdust ◽  
Adsorption Capacities ◽  
Initial Ph ◽  
Surface Modified

Objectives : The physicochemical characteristics of Mg-biochar composites derived from kelp and pine after pretreatment with MgCl2 were analyzed, and their adsorption capacities for an anionic dye, Congo red (CR), were evaluated.Methods : After pretreating 60 g of kelp and pine sawdust in 1 L of 0.1 M MgCl2･6H2O, the raw materials were pyrolyzed at 500℃ to produce Mg-biochar composites (kelp based KB-Mg and pine based PB-Mg). The fundamental physicochemical characteristics of the Mg-biochar composites were examined, and their adsorption capacities for CR were investigated using different initial pH values, adsorption kinetic models, and adsorption isotherm models.Results and discussion : The Mg-biochar composites showed the development of uniform deposits of Mg minerals primarily as MgO crystal on the surface by the surface modification with MgCl2. When the pristine biochars were surface-modified with MgCl2, their adsorption capacities for CR were significantly increased over the entire pH range tested. The CR adsorption process by all biochars was best described with the pseudo-first order kinetics model, and the adsorption isotherm characteristics were better described with the Langmuir isotherm model for all biochars. The Langmuir maximum adsorption capacities for KB-Mg and PB-Mg were 423.0 mg/g and 394.7 mg/g, respectively. It is suggested that the main mechanism for CR adsorption on the Mg-biochars is electrostatic attraction between CR and the biochars.Conclusions : The results showed that surface modification with MgCl2 could greatly enhance the CR adsorption capacity of biochars, and the results demonstrated the great potential of KB-Mg and PB-Mg for CR removal.

Experimental Study of Adsorption of Ammonia Nitrogen from Wastewater onto the Bagasse Adsorbent

2014 ◽  
Vol 529 ◽  
pp. 22-25 ◽  
Author(s):  
Li Wei Xie ◽  
Ze Long Xu ◽  
Yan Hua Huang ◽  
Shuang Cao ◽  
Zong Qiang Zhu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Experimental Study ◽  
Adsorption Capacity ◽  
Ammonia Nitrogen ◽  
Alkaline Condition ◽  
Maximum Adsorption Capacity ◽  
Initial Concentration ◽  
Adsorption Capacities ◽  
Neutrality Condition ◽  
Adsorbent Dose

Adsorption of ammonia nitrogen from aqueous solution onto the bagasse adsorbent has been investigated to evaluate the effects of Adsorbent dose, initial NH4+-N concentration, and pH on the removal systematically. With increasing initial concentration, the amount of ammonia nitrogen sorbed onto the adsorbent increased until it gradually decreased due to the initial concentration exceed 50 mg·L-1, and the maximum adsorption capacity was observed for the sample to be 1.31 mg·g-1 at the initial concentration of 30 mg·L-1, and the corresponding removal rates decreased from 94.01 to 3.89%, with increase in initial concentration from 5 to 100 mg·L-1. Adsorption capacities decreased from 6.04 to 0.49 mg·g-1 with increasing adsorbent dose from 0.1 to 1.5g. What’s more, under alkaline condition, the removal efficiency of ammonia nitrogen from aqueous solution onto the samples were superior to that under acidity and neutrality condition.

Physico-chemical modification of natural mordenite-clinoptilolite zeolites and their enhanced CO2 adsorption capacity

2020 ◽  
Vol 294 ◽  
pp. 109871 ◽  
Author(s):  
Satriyo Krido Wahono ◽  
Joseph Stalin ◽  
Jonas Addai-Mensah ◽  
William Skinner ◽  
Ajayan Vinu ◽  
...  
Keyword(s):  
Chemical Modification ◽  
Adsorption Capacity ◽  
Co2 Adsorption ◽  
Physico Chemical ◽  
Co2 Adsorption Capacity

scholarly journals Toward an effective use of laser-driven very high energy electrons for radiotherapy: Feasibility assessment of multi-field and intensity modulation irradiation schemes

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Luca Labate ◽  
Daniele Palla ◽  
Daniele Panetta ◽  
Federico Avella ◽  
Federica Baffigi ◽  
...  
Keyword(s):  
High Energy ◽  
High Dose Rate ◽  
High Dose ◽  
Feasibility Assessment ◽  
High Energy Electrons ◽  
Very High Energy ◽  
Effective Use ◽  
Dose Deposition ◽  
Therapeutic Doses ◽  
Very High

Abstract Radiotherapy with very high energy electrons has been investigated for a couple of decades as an effective approach to improve dose distribution compared to conventional photon-based radiotherapy, with the recent intriguing potential of high dose-rate irradiation. Its practical application to treatment has been hindered by the lack of hospital-scale accelerators. High-gradient laser-plasma accelerators (LPA) have been proposed as a possible platform, but no experiments so far have explored the feasibility of a clinical use of this concept. We show the results of an experimental study aimed at assessing dose deposition for deep seated tumours using advanced irradiation schemes with an existing LPA source. Measurements show control of localized dose deposition and modulation, suitable to target a volume at depths in the range from 5 to 10 cm with mm resolution. The dose delivered to the target was up to 1.6 Gy, delivered with few hundreds of shots, limited by secondary components of the LPA accelerator. Measurements suggest that therapeutic doses within localized volumes can already be obtained with existing LPA technology, calling for dedicated pre-clinical studies.

scholarly journals Performance of metal–organic frameworks for the adsorptive removal of potentially toxic elements in a water system: a critical review

RSC Advances ◽  
2019 ◽  
Vol 9 (59) ◽  
pp. 34359-34376 ◽  
Author(s):  
Sammani Ramanayaka ◽  
Meththika Vithanage ◽  
Ajit Sarmah ◽  
Taicheng An ◽  
Ki-Hyun Kim ◽  
...  
Keyword(s):  
Partition Coefficient ◽  
Critical Review ◽  
Toxic Elements ◽  
Metal Organic Frameworks ◽  
Water System ◽  
Potentially Toxic Elements ◽  
Adsorptive Removal ◽  
System A ◽  
Adsorption Capacities ◽  
Metal Organic

This review examines the performance of metal–organic frameworks based on partition coefficient data over the classic maximum adsorption capacities.

scholarly journals Effect of chemical aging of Alternanthera philoxeroides-derived biochar on the adsorption of Pb(II)

2019 ◽  
Vol 80 (2) ◽  
pp. 329-338
Author(s):  
Xuan Wang ◽  
Yande Jing ◽  
Yongqiang Cao ◽  
Shuo Xu ◽  
Lidong Chen
Keyword(s):  
Adsorption Capacity ◽  
Structural Changes ◽  
Aging Treatment ◽  
Alternanthera Philoxeroides ◽  
Order Kinetic ◽  
Adsorption Effect ◽  
Chemical Aging ◽  
Adsorption Capacities ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Abstract In this study, biochar was prepared from Alternanthera philoxeroides (AP) under O2-limited condition at 350 °C (LB) and 650 °C (HB) and treated with aging by HNO3/H2SO4 oxidation. Structural changes of the biochar after aging treatment and the treatment's effect on Pb(II) absorption were explored. The results showed that oxygen-containing functional groups, aromatic structure and surface area of the biochar increased after the aging treatment. However, the integrity of the tubular structure was broken into fragments. The adsorption process of Pb(II) was in accordance with the pseudo-second-order kinetic model and fitted by the Langmuir model. With the increase of pH, the adsorption capacities of Pb(II) increased gradually, and the adsorption effect was best at pH 5. The aged HB presented a decrease of the carboxyl group, which caused less adsorption capacity of Pb(II) than that of aged LB. The maximum adsorption capacities of Pb(II) on fresh biochar at 350 °C and 650 °C were 279.85 and 286.07 mg·g−1 and on aged biochar were 242.57 and 159.82 mg·g−1, respectively. The adsorption capacity of HB for Pb(II) was higher than that of LB, and the adsorption capacity of aged biochar for Pb(II) decreased obviously, which might be attributable to changes in physicochemical properties of biochar after the aging treatment.

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