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Questions and Answers
Which leaf type reached equilibrium for Methylene Blue removal in 60 minutes?
Which leaf type reached equilibrium for Methylene Blue removal in 60 minutes?
Which treatment allowed Guava leaves to retain 60% of their initial capacity after one regeneration cycle?
Which treatment allowed Guava leaves to retain 60% of their initial capacity after one regeneration cycle?
What pH conditions were optimal for Magnolia leaves in removing Cr6+?
What pH conditions were optimal for Magnolia leaves in removing Cr6+?
What modification was applied to pineapple leaves for Pb2+ removal?
What modification was applied to pineapple leaves for Pb2+ removal?
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Which of the following leaves exhibited higher adsorption capacity than their activated carbon counterpart?
Which of the following leaves exhibited higher adsorption capacity than their activated carbon counterpart?
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What was the percentage increase in adsorption capacity for uranyl ions after modifying the peel?
What was the percentage increase in adsorption capacity for uranyl ions after modifying the peel?
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Which of the following adsorbents was reported to have the highest adsorption capacity for Methylene Blue?
Which of the following adsorbents was reported to have the highest adsorption capacity for Methylene Blue?
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In which pH range did grapefruit peel achieve optimum adsorption for Pb2+?
In which pH range did grapefruit peel achieve optimum adsorption for Pb2+?
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What modification was applied to grapefruit peel to enhance its adsorption properties?
What modification was applied to grapefruit peel to enhance its adsorption properties?
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Which citrus peel adsorbent was used for the removal of reactive dye, Reactive Red?
Which citrus peel adsorbent was used for the removal of reactive dye, Reactive Red?
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Which adsorbent showed an adsorption capacity of 566 mg g−1 for ciprofloxacin?
Which adsorbent showed an adsorption capacity of 566 mg g−1 for ciprofloxacin?
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What substance was orange peel found to adsorb with a capacity of 4.80 mg g−1?
What substance was orange peel found to adsorb with a capacity of 4.80 mg g−1?
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Which type of peel had a significant adsorption capacity for reactive dye, achieving 344.8 mg g−1?
Which type of peel had a significant adsorption capacity for reactive dye, achieving 344.8 mg g−1?
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What modification process was used on rice husks to aid in Co2+ removal?
What modification process was used on rice husks to aid in Co2+ removal?
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What was the optimal pH for the adsorption of nitrates from water using modified rice husks?
What was the optimal pH for the adsorption of nitrates from water using modified rice husks?
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How long was the equilibrium time for the adsorption of Pb2+ using rice husks?
How long was the equilibrium time for the adsorption of Pb2+ using rice husks?
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What chemical treatment was used on almond green hulls for enhancing Co2+ adsorption?
What chemical treatment was used on almond green hulls for enhancing Co2+ adsorption?
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What was observed about the particle size after modification of rice husks?
What was observed about the particle size after modification of rice husks?
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Which of the following adsorbents was used for the removal of Cr6+ at an equilibrium time of 60 minutes?
Which of the following adsorbents was used for the removal of Cr6+ at an equilibrium time of 60 minutes?
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What effect did the alkaline treatment have on the surface of rice husks?
What effect did the alkaline treatment have on the surface of rice husks?
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What was the influence of the presence of other anions on nitrate removal effectiveness?
What was the influence of the presence of other anions on nitrate removal effectiveness?
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Which natural material showed the highest adsorption capacity for Methylene Blue?
Which natural material showed the highest adsorption capacity for Methylene Blue?
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What effect does pH have on the adsorption of adsorbates according to the findings?
What effect does pH have on the adsorption of adsorbates according to the findings?
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Which seed was treated with hydrochloric acid and aluminum chloride for adsorption purposes?
Which seed was treated with hydrochloric acid and aluminum chloride for adsorption purposes?
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Which compound was NOT mentioned in relation to Nigella sativa seeds?
Which compound was NOT mentioned in relation to Nigella sativa seeds?
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What characteristic was improved in the adsorption performance of Paeonia ostii seed coats?
What characteristic was improved in the adsorption performance of Paeonia ostii seed coats?
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Which seed exhibited antibacterial properties while removing Methylene Blue?
Which seed exhibited antibacterial properties while removing Methylene Blue?
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What factor contributed to the high rate of As5+ removal compared to F− for modified guava seeds?
What factor contributed to the high rate of As5+ removal compared to F− for modified guava seeds?
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Which dye was used with psyllium seeds in the adsorption study?
Which dye was used with psyllium seeds in the adsorption study?
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Which seed showed the highest adsorption capacity for Methylene Blue?
Which seed showed the highest adsorption capacity for Methylene Blue?
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What functional groups in seeds interact with sulfur and nitrogen atoms of Methylene Blue?
What functional groups in seeds interact with sulfur and nitrogen atoms of Methylene Blue?
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At what pH level were date pits most effective in adsorbing Methylene Blue?
At what pH level were date pits most effective in adsorbing Methylene Blue?
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What adsorption mechanism occurs at low pH for date pits when removing Methylene Blue?
What adsorption mechanism occurs at low pH for date pits when removing Methylene Blue?
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How does chitosan coating affect black sesame seed's adsorption capacity?
How does chitosan coating affect black sesame seed's adsorption capacity?
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Which of the following pollutants were specifically mentioned to be removed by jujube seeds?
Which of the following pollutants were specifically mentioned to be removed by jujube seeds?
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What is the primary component of stones or pits mentioned in the content?
What is the primary component of stones or pits mentioned in the content?
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Which plant's seeds were used for remediation of water contaminated with Reactive Orange 16?
Which plant's seeds were used for remediation of water contaminated with Reactive Orange 16?
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Study Notes
Rice Husk Modification and Adsorption
- Rice husk modification methods include sonication and supercritical CO2 treatment to remove silica and lignin, exposing more OH groups for adsorption.
- These modifications increase the specific surface area without changing particle size, but decrease ash content and the point of zero charge.
- Optimal adsorption conditions for Co2+ removal were pH 5 and 300 minutes equilibrium time.
- NaOH modification of rice husks for Methylene Blue adsorption caused surface ruptures, exposing internal structure and increasing adsorption sites.
- Epichlorohydrin and dimethylamine-modified rice husks were used for nitrate adsorption, with optimal pH 7 and 90-minute equilibrium time. Nitrate removal was affected by the presence of other anions (CO32− > Cl− > PO43− > SO42−).
- Rice husks also effectively adsorbed U6+, Direct Red 31, Direct Orange 26 (pH 2, 200 min), Tl3+ (pH 10, 20 min), and Cd2+ (pH 5, 60 min). Pb2+ showed higher affinity than Cd2+.
Other Plant Husks as Adsorbents
- Almond green hulls, treated with H2O2 and ammonia, adsorbed Co2+ with a 1-minute equilibrium time due to increased surface area.
- Untreated almond green hulls adsorbed Cr6+ (pH 2, 60 min equilibrium).
- Green longan husks removed Ni2+ and Cd2+ (pH 5, 20 min equilibrium).
- Mustard husk adsorbed Pb2+ (pH 4) and Cd2+ (pH 8).
- Pistachio hulls adsorbed Methylene Blue (pH 8, 70 min) and cyanide (pH 10, 60 min).
Plant Leaves as Adsorbents
- Many plant leaves, composed mainly of cellulose, lignin, and hemicellulose, were tested for pollutant removal. Pretreatment is often used.
- Aloe vera leaves adsorbed Titan Yellow dye, exhibiting higher capacity than activated carbon.
- Guava leaves adsorbed phenol, reaching equilibrium in 9 hours; 60% capacity retained after one regeneration cycle with NaOH.
- Lesser bulrush leaves removed Methylene Blue (pH 10, 60 min).
- Magnolia leaves adsorbed Cr6+ (pH 2, 45 min); HNO3 was a better desorbing agent than HCl or EDTA.
- Pineapple leaves, modified with NaOH and iminodiacetic acid, adsorbed Pb2+; the iminodiacetic acid modification showed higher adsorption capacity and slower regeneration decay.
- Pomelo leaves adsorbed Methylene Blue; a modified version showed higher adsorption capacity for uranyl ions.
Citrus Peels as Adsorbents
- Various citrus peels (orange, pomelo, grapefruit, lemon, tangerine, shaddock) were used to remove different pollutants. Modifications often enhanced adsorption capacity.
- Modifications included treatment with acetone, quaternary amines, Fe2O3-PDMS, NaOH, and citrate.
- Adsorption capacities varied widely depending on the peel type, modification, and target pollutant.
Plant Seeds as Adsorbents
- Many plant seeds (papaya, pergularia tomentosa, populus tremula, psyllium, tamarind, wormwood, jujube, black caraway, chia, mango, black sesame, etc.) were employed as adsorbents, often after pretreatment or modification.
- Adsorption is often influenced by pH, with many showing optimum at acidic pH.
- Modifications included defatting, aluminum treatment, chitosan coating, and NaOH treatment to remove lignin and hemicellulose.
- Some seeds (e.g., black caraway) were used in composite materials with metal oxides showing enhanced properties.
Plant Stones/Pits as Adsorbents
- Date pits adsorbed Methylene Blue, with adsorption mechanisms varying depending on pH (ion exchange at low pH, electrostatic attraction at high pH).
- Date pits were also used to remove Basic Red 2 and Methyl Violet.
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Description
This quiz explores the various modification techniques of rice husks for enhanced adsorption properties. Topics include the impact of sonication, supercritical CO2 treatment, and NaOH modifications on adsorption efficiencies for various contaminants like Co2+, Methylene Blue, and nitrates. Test your understanding of optimal conditions and the factors affecting adsorption performance.
