Mostafa 2022 - chitosan graft copolymer mercury removal

Mostafa synthesized a poly(meth acrylamide)-chitosan nanoparticle graft copolymer and tested its ability to remove mercury ions from aqueous solution. This is in-scope a2 mitigation and wastewater-removal evidence for mercury, not food, palm oil, or personal-care occurrence.

Key numbers

The mercury-removal solution was prepared as 208 ppm mercury ions by dissolving 0.33 g mercuric acetate in 1 L double-distilled water. Chitosan nanoparticles and poly(meth acrylamide)-chitosan nanoparticle graft copolymers were tested at 0.5-3.0 g dosage. The paper states that all experiments were conducted in triplicate.

Figure 4 conditions were mercury ions 208 ppm, total volume 100 mL, time 30 min, pH 7, and temperature 30 +/- 1 degrees C. Increasing dosage from 0.5 to 3.0 g gradually decreased residual Hg in filtrate and leveled off at 2.5 g. The text reports maximal residual mercury of 70 ppm for the graft copolymer and 120 ppm for chitosan nanoparticles. The same sentence reports those as 62.98% and 42.3.0% removal, respectively; the paper’s percentage text is internally inconsistent with 208 ppm to 70 ppm, so both the residual concentration and the source-printed percentage are retained as paper-side values.

Figure 5 tested grafting extent from 17.3% to 50.2% at polymer dosage 2.5 g, mercury ions 208 ppm, total volume 100 mL, time 30 min, pH 7, and temperature 30 +/- 1 degrees C. Increasing grafting extent to 50.2% decreased residual mercury ion concentration from 208 ppm to 70 ppm at pH 7. The paper reports this as 66.36% removal.

Figure 6 compared unrecovered and recovered copolymer after recovery using 1 N HNO3 at pH 2. For the 50.2% graft-yield copolymer, the recovered material reduced mercury ion content to 99 ppm compared with 70 ppm for unrecovered material.

Optimum grafting conditions reported in the conclusion were chitosan nanoparticles 1.0 g, potassium chromate 100 mmol/l, mandelic acid 80 mmol/l, sulphuric acid 100 mmol/l, meth acrylamide 150% based on weight of substrate, reaction time 120 min, and reaction temperature 45 degrees C.

Methods (brief)

Chitosan nanoparticles were prepared from native chitosan and meth acrylic acid, then grafted with meth acrylamide under nitrogen using potassium chromate and mandelic acid as a redox pair. Graft yield was estimated by titrimetric nitrogen analysis. FTIR and thermogravimetric analysis characterized the graft copolymer. Mercury removal used mercuric acetate solution, 15 min agitation at room temperature to form a polymer-mercury complex, filtration, and atomic absorption spectrophotometry on the filtrate for residual metals.

Implications

Certification: Do not use these values as food, ingredient, or product occurrence. They are bench-scale mercury-removal values in spiked aqueous solution.

Courses: Useful mitigation example for chitosan-derived biosorbents and for teaching why recovered sorbent performance must be distinguished from fresh sorbent performance.

App: Context only. The source can support remediation and wastewater-treatment background, not consumer-product scoring.

Wiki pages this source may touch

• remediation-evidence
• mercury-total

Verification notes

Recovered from skip:not-food-occurrence under the 2026-06-10 inclusion-by-default rule. The old skip treated the paper as out of scope because it was not food or personal-care occurrence. On reading, it is in-scope a2 mitigation/remediation evidence because it reports mercury-ion removal from aqueous solution.

Numbers were checked against the abstract, Methods, Figure 4-6 captions, mercury-removal prose, recovery section, and conclusion in the extracted PDF. Mercury is recorded as tHg because the source reports mercury ions from mercuric acetate and does not discuss methylmercury or other mercury speciation. Products and ingredients are intentionally empty. The source’s apparent removal-percentage inconsistency around 208 ppm to 70 ppm is noted rather than corrected.

Page history

The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.