Binary Systems of Kaolinite and Hematite: Preparation, Characterization and Adsorption Characteristics for Fluoride

Wei, Shaozhong; Niu, Pengju; Wang, Rui; Fang, Dun; Yang, Xiaohong; Dan, Youmeng

doi:10.2320/matertrans.m2015448

Cited by 5 publications

(2 citation statements)

References 27 publications

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“…The BC used in all these experiments was of same batch with particle size distribution as shown in Figure 2 and the MCRW was collected once with physical properties as shown in Table 3. The capacity of adsorbents to adsorb a solute from a solution is expressed in grams of solute adsorbed per gram of adsorbent (Wei et al, 2016). For this study, BC fluoride removal capacity was estimated by considering a fixed amount of mg of fluoride adsorbed.…”

Section: Comparison Of Adjusting Mcrw Ph and Treatment Of Bc With Acid Before Use On Defluoridationmentioning

confidence: 99%

Practical Approach for Removal of Natural Organic Matter and defluoridation of Maji ya Chai river Water: Use of Acid Pre-treated Bone Char and Coagulants

Minja

2019

TJET

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The removal of natural organic matter (NOM) and fluoride from Maji ya Chai River water (MCRW) using bone char (BC) and coagulants was investigated. Fine BC particles ranging from 0.045 to 0.2 mm were used in a 1 litre half-filled container, stirred at 300 rpm for 60 min followed by addition of a commercial coagulant and allowed to settle for 24 hours to remove NOM. MCRW practicable and affordable defluoridation method for removal of NOM through defluoridation with BC pre-treated with 0.3 N HCl followed by coagulation with Poly-aluminium chloride (PACl) is proposed. Reduction of fluoride from 21 mg/L to 1.7 mg/L was achieved by use of 5 g/L of 0.3 N HCl acid pre-treated BC and 66 mL of 1% PACl per litre of MCRW. The acid pre-treated BC was found to double defluoridation capacity of BC, while adjustment of pH of MCRW with HCl acid to pH 3 has tripled defluoridation capacity of BC. The 0.3 N HCl acid pre-treated BC is preferred to avoid impractical working with acid solution for pH adjustment in households and communities. The treated water pH was within the acceptable portable water range of 6.5 to 8.5. PACl is a preferable coagulant for removal of NOM from MCRW since it is more effective and safer compared to use of alum and zetafloc 703.

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Section: Comparison Of Adjusting Mcrw Ph and Treatment Of Bc With Acid Before Use On Defluoridationmentioning

confidence: 99%

Practical Approach for Removal of Natural Organic Matter and defluoridation of Maji ya Chai river Water: Use of Acid Pre-treated Bone Char and Coagulants

Minja

2019

TJET

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“…Fluoride adsorption has been extensively studied with respect to specific soil components kaolinite and bentonite (Anderson, Zelazny, & Bertsch, 1991;Bar-Yosef, Afik, & Rosenberg, 1988;Kau, Smith, & Binning, 1998), aluminium and iron hydroxide minerals (Hiemstra & Van Riemsdijk, 2000;Meeussen, Scheidegger, Hiemstra, VanRiemsdijk, & Borkovec, 1996;Nordin, Sullivan, Phillips, & Casey, 1999) and a binary clay-mineral (kaolinitehaematite) substrate system (Wei et al, 2016). These studies have demonstrated that F − adsorption by individual soil components generally results in increased solution pH, attributable to anion exchange between F − and surface OH − groups.…”

Section: Introductionmentioning

confidence: 99%

Oxalate‐fluoride anion exchange in alpine tundra soil: Impact on aluminium transport

Evans

Jacobs

2020

European J Soil Science

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Anion exchange between ubiquitous low-molecular-weight organic acids (LMWOA), such as oxalate, and surface-retained inorganic anions, such as F − , SO 4 2− and OH − , can play a critical role in Al bioavailability and transport in acidic alpine tundra soil. A series of batch equilibration and composite soil column leaching studies were conducted to examine anion exchange reactions between F − , oxalate and OH − , and the impact of increased soil solution F − concentration on Al transport. The addition of either F − or oxalate to soil suspensions resulted in significantly higher solution pH, suggesting F − and oxalate exchange with surface -OH groups. Distinct stages of OH − release were observed for all soil horizons leached with 1.32 × 10 −3 mol l −1 F − , with OH − release decreasing in the order O/A1~A2> > Bw. A similar OH − release pattern was observed in the O/A1 horizon for the 7.81 × 10 −4 mol l −1 oxalate treatment, suggesting that both F − and oxalate may be competing for common exchange sites in the O/A1 horizon. Fluoride displacement by oxalate, in batch equilibration experiments, was observed for both the 2.84 × 10 −4 mol l −1 and 7.81 × 10 −4 mol l −1 oxalate treatment. Individual soil horizons leached with 7.81 × 10 −4 mol l −1 oxalate exhibited increased F − leaching in the order O/A1 > A2~Bw, with pulsed F − movement being observed in the O/A1 horizon. Soil columns eluted with 1.32 × 10 −3 mol l −1 F − exhibited increased Al solubilization and transport, with Al leaching increasing in the order Bw > A2 > O/A1. Sequential leaching of soil columns in the order D. I. H 2 O ! 1.32 × 10 −3 mol l −1 F − ! D.I. H 2 O ! 7.81 × 10 −4 mol l −1 oxalate indicated that previously adsorbed F − was displaced by oxalate. Displacement of F − by oxalate increased in the order O/A1 > A2 > Bw. Hydroxyl displacement by both F − and oxalate may be an important source of acid neutralization in a soil wetting front, affecting Al speciation and transport. Highlights• Oxalate and F − compete for similar OH − exchange sites, increasing soil pH.• Adsorbed F − can be displaced by oxalate anions.• Al solubilization increases with F − adsorption in alpine tundra soil.

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Characteristics and effects of fluorine release from shallow high-fluoride soils

et al. 2019

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Binary Systems of Kaolinite and Hematite: Preparation, Characterization and Adsorption Characteristics for Fluoride

Cited by 5 publications

References 27 publications

Practical Approach for Removal of Natural Organic Matter and defluoridation of Maji ya Chai river Water: Use of Acid Pre-treated Bone Char and Coagulants

Practical Approach for Removal of Natural Organic Matter and defluoridation of Maji ya Chai river Water: Use of Acid Pre-treated Bone Char and Coagulants

Oxalate‐fluoride anion exchange in alpine tundra soil: Impact on aluminium transport

Characteristics and effects of fluorine release from shallow high-fluoride soils

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