Adsorption of Humic Acid from Water Using Chemically Modified Bituminous Coal-based Activated Carbons

Abstract

Humic acid (HA) impairs water quality due to its reactivity with many substances present in water. During the drinking-water treatment process and water distribution via water supply system, HA present in water may react with chlorine and other disinfects <br /> producing harmful disinfection by-products (DBPs), which are categorized by the International Agency for Research on Cancer (IARC) in groups 2A (probably carcinogenic to humans) or 2B (possibly carcinogenic to humans). Several studies have investigated and reported increased HA removal by iron-coated sorbents. Therefore, the aim of this study was to examine the removal of HA from water by two commercially available bituminous coal-based activated carbons (ACs), Cullar D (Cm) and Hydraffin 30N (Hm). Prior to testing the chosen adsorbents were chemically modified according to two protocols: (1) oxidation by acid mixture (m1), and (2) oxidation with acid mixture followed by iron-ions impregnation (m2). The batch adsorption tests were used to test their efficiency in HA removal under various values of process parameters (initial HA concentration, pH, contact time, adsorbent mass, and temperature). The results showed that up to 96 % of HA removal can be obtained by Cullar D modification Cm1, while maximum uptake of HA by Hydraffin 30N modification was achieved with Hm1 (62.1 %). After surface saturation with Fe3+ –ions (m2), both activated carbons showed similar and lower performances in HA removal (Cm2 up to 66.5 %, and Hm2 up to 50.3 %). FTIR analysis confirmed differences in modified AC structures, as well as favorable structure of Cm1 for HA adsorption.

Quaternization of Porous Cellulose Beads and Their Use for Removal of Humic Acid from Aqueous Medium

“…In adsorption methods, porous materials are widely used as an adsorbent matrix. Activated carbons produced from different kinds of agricultural materials have been prepared to be applied to the removal of HA in many articles [13][14][15]. However, their use is frequently limited because of disadvantages, such as high cost for chemical activation, slow adsorption rate, low adsorption capacity, and difficulty of regeneration.…”

Synergistic Removal of U (VI), Pb(II), and HA on nZVI/MoS2 Composites Investigated by Batch, Spectroscopic, and Modeling Techniques

“…Interestingly, the adsorption of HA on nZVI/MoS 2 slightly decreased with the pH increasing from 3.0 (95%) to 11.0 (82%, Figure C). The high adsorption of HA at low pH was due to the electrostatic attraction of positively charged nZVI/MoS 2 and the negatively charged HA at a low pH. ,, Moreover, high solubility of HA was observed at acidic conditions, which enhanced the HA adsorption. , In addition, inner-/outer-sphere complexations dominated HA adsorption at high pH due to the large amount of dissociated carboxylic and phenolic groups . Thus, high adsorption of U­(VI) and Pb­(II) was observed at high pH, while HA removal decreased with increasing pH.…”

“…With the rapid development of modern industrialization and civilization, the increasing production of various environmental pollutants (e.g., organics, heavy metals, and radionuclides) has been paid more attention due to the high toxicity, carcinogenicity, and hazardous bioaccumulation. − For instance, uranium (e.g., dissolved U­(VI) and sparingly dissolved U­(IV)) has been widely used as basic raw materials for nuclear energy. , Lead (Pb­(II)) as a typical heavy metal has been utilized in various industries such as milling, processing, printing, storage batteries, and smelting. ,− Natural organic matter (NOM, such as humic acid (HA) and fulvic acid (FA)) is an integral component of aquatic systems, which possesses a complex structure with a high molecular weight. − Additionally, the fate and transport of heavy metal/radionuclides are significantly influenced by organics due to the formation of stable complexes. ,− Thus, it is of great importance to remove heavy metals, radionuclides, and HA simultaneously in actual environmental remediation. − Various removal methods, including ion exchange, chemical precipitation, membrane separation, redox, osmosis, and adsorption, have been widely investigated to remove environmental pollutants in recent years. , Among them, adsorption and redox are simple and effective techniques. , The development of cost-efficient adsorbents with high adsorption performance, large reduction ability, and exceptional selective enrichment is of great significance for the elimination of radionuclides, heavy metals, and organics from aqueous solutions …”

Kinetic, Isothermal, and Thermodynamic Analyses of Adsorption of Humic Acid on Quaternized Porous Cellulose Beads

“…Activated carbons produced from different agricultural wastes have been frequently used in many studies on the adsorptive removal of HA [6,[12][13][14]. However, some problems to be solved are raised; for example, the cost for chemical activation is high, the regeneration is difficult, the adsorption rate is low, and the adsorption capacity is low [15][16][17]. Therefore, their use is frequently limited.…”