Wyniki wyszukiwania - BazTech

Ograniczanie wyników

1 Journal of Ecological Engineering

1 2025

Znaleziono wyników: 1

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Effectiveness of hematite derived from iron sand for adsorbing chromium (VI) – Characterization, isotherm models, and thermodynamics

Susanti Evi, Fathimah Assyadatina, Zulti Fifia, Nafisyah Eva, Rosidah, Latief Sutanto

Journal of Ecological Engineering

2025

Vol. 26, nr 1

223--233

The industry has suffered major chromium wastewater issues. Chromium is a heavy metal that can threaten both nature and people’s health. Adsorption is a simple, environmentally friendly, and effective process for removing chromium from wastewater. Iron sand is an alternate adsorbent that can adsorb chromium. The iron sand in this research originated from Sukabumi, Indonesia, with a hematite content of 63.335%. The goal of this study is to evaluate the adsorption mechanism of hematite based on adsorbent weight, Cr(VI) initial concentration, pH of the solution, and contact time. This study was conducted experimentally throughout multiple phases. First, hematite was characterized using XRD, BET, FTIR and XRF to assess crystal structure, mineral composition, surface area, functional groups and the percentage of hematite in iron sand. Subsequently, the pH and contact time were optimized. The highest adsorption capacity is then determined using the Langmuir and Freundlich isotherms. The study found that hematite has a surface area before and after adsorption of 619.486 m2/g and 334.783 m2/g, with XRD peaks at 2θ = 33.037° and 35.357°, Fe-O bonds with a wavelength of 647.17 cm-1 and hematite content of 63.335%. Optimal Cr(VI) adsorption occurs at pH 1, with a contact time of 120 minutes, Cr(VI) concentration of 50 mg/L, 5.0 g mass of hematite, with an adsorption capacity (Qe), and adsorption efficiency (%) of 3.83 mg/g and 75.95%. The Freundlich isotherm model accurately represents adsorption, revealing a heterogeneous surface. The linear equation of the Freundlich curve is Log Qe = 0.1152 Log Ce + 0.6376, R2 = 0.9999, with the value of adsorption capacity (kf) = 4.3411 mg/g and adsorption intensity (n) = 8.681. The enthalpy of adsorption (ΔHads) at a concentration of 20 mg/L, 2.5 g, pH 3, and 30 minutes is -95.852 kJ/mol, indicating chemisorption.