Stability Improvement of Humic Acid as Sorbent through Magnetite and Chitin Modification

Abstract

Stability improvement of humic acid (HA) through modification of HA by chitin (HA-chitin) followed by a coating of HA-chitin on magnetite has been successfully performed. The coated magnetite (magnetite/HA-chitin) was conducted by the co-precipitation method, and the synthesized magnetite/HA-chitin was characterized by FT-IR, XRD, SEM-EDX, and VSM. The successful coated-magnetite by HA-chitin was proved by the appearance of a new band at 1627 cm-1 (FT-IR), the formation of a crystalline phase with characteristic 2θ of magnetite: 30.259° [220]; 35.64° [311]; 42.590° [400]; 57.280° [511]; and 62.896° [440] (XRD), an increasing of carbon content in magnetite/HA-chitin (SEM-EDX), and the ease of magnetite/HA-chitin being attracted to external magnetic fields with magnetic saturation strength 29.3 emu/g (VSM). Stability tests at pH 2.0 - 10.0 prove that magnetite/HA-chitin remains stable as a solid sorbent on average above 80%. Its application to Hg (II) sorption occurred optimum at pH 7.0, where 75.89% Hg (II) is sorbed on 0.1 g of sorbent and agreed well to the pseudo-second-order kinetics model of Ho.

The Dependency of Kinetic Parameters as a Function of Initial Solute Concentration: New Insight from Adsorption of Dye and Heavy Metals onto Humic-Like Modified Adsorbents

“…Similarly, HDHA-Fe3O4 show the improved stability until pH 10 with the 83% remained weight. The stability improvement of HA or HA-like substance by Fe3O4 incorporation has been widely reported [23,27,[35][36][37]. The results indicate that modification of HDHA with the chitin and Fe3O4 has improved the stability in alkaline solution.…”

Remazol Briliant Blue Uptake by Green and Low-Price Black Carbon from Ilalang Weeds (Imperata cylindrica) Activated by KOH Solution

“…photodegradation [6][7], membrane exchange [8], and biodegradation using plants, as well as adsorption [9] [10]. The use of adsorbents via the adsorption method has grown in popularity because the system is simple, environmentally friendly, and cost-effective [11], [12]. The development of cellulose-based adsorbent materials in the form of activated carbon (AC)…”

Adsorpsi Methylene Blue pada Nanopartikel Magnetit tersalut Asam Humat: Kajian Isoterm dan Kinetika

“…Asam humat dikenal dapat berinteraksi dengan lebih dari 50 senyawa yang terdiri dari ion logam berat, senyawa radioaktif, dan polutan organik (termasuk zat warna) [12]. Walaupun AH memiliki keunggulan sebagai adsorben, namun AH memiliki beberapa kelemahan diantaranya kestabilan yang rendah pada pH basa, mudah mengalami aglomerasi, dan pemisahan pasca adsorpsi yang relatif sulit [13].…”

“…Para peneliti sebelumnya telah melakukan modifikasi untuk meningkatkan kestabilan dan kapasitas adsorpsi AH diantaranya dengan menggunakan kitin [13,14], karboksimetilselulosa (CMC) [15], perlit [16], titanium dioksida [17], attapulgit [18], dan magnetit [19][20][21]. Selain meningkatkan kestabilan dan kapasitas adsorpsi, modifikasi AH dengan magnetit juga memudahkan pengumpulan kembali adsorben pasca adsorpsi dengan magnet eksternal.…”