Adsorption of anionic dyes in aqueous solution using chemically modified barley straw.

Area of Science:

• Environmental Chemistry
• Materials Science
• Agricultural Science

Background:

• Industrial wastewater often contains persistent anionic dyes.
• Conventional treatment methods can be costly and inefficient.
• Agricultural waste offers a potential source for low-cost adsorbents.

Purpose of the Study:

• To develop and characterize a novel adsorbent from modified barley straw for anionic dye removal.
• To investigate the adsorption mechanism and efficiency of the adsorbent for Acid Blue (AB40) and Reactive Blue 4 (RB4).
• To evaluate the stability and reusability of the adsorbent.

Main Methods:

• Barley straw was chemically modified using NaOH and hexadecylpyridinium chloride monohydrate (CPC).
• Batch adsorption experiments were conducted to study the effects of contact time, initial dye concentration, and pH.
• Adsorbent characterization included FT-IR and elemental analysis.
• Adsorption kinetics and isotherms were analyzed using pseudo-second-order and Langmuir models, respectively.

Main Results:

• The modified barley straw adsorbent (BMBS) demonstrated strong attachment of CPC to its surface.
• High removal percentages for AB40 and RB4 were achieved, increasing with contact time.
• Adsorption was most effective under highly acidic conditions.
• Maximum adsorption capacities were 51.95 mg/g for AB40 and 31.5 mg/g for RB4 at 25°C.
• Adsorption kinetics followed the pseudo-second-order model, and isotherms fitted the Langmuir model.

Conclusions:

• Chemically modified barley straw is an effective and stable adsorbent for anionic dyes.
• The adsorbent exhibits significant potential for removing Acid Blue and Reactive Blue from aqueous solutions.
• This approach offers a sustainable and cost-effective method for industrial wastewater treatment.