Functionalized layered double hydroxide with compound to remove cationic and anionic pollutants: A review

Layered double hydroxide (LDH) is one of the promising clay minerals that show great potential in various applications owing to its versatile structural properties. Prominently known for its high anion exchange capacity, this allows LDH to be considered as one of the most effective adsorbents in removing anionic toxic. However, the structural property of LDH hinders it from removing cationic toxic. Therefore, LDH have been functionalized to enhance its adsorption properties. In the present work, we aim to summarize the recent progress of functionalized LDH with different compounds for removal of both anionic and cationic toxics. The adsorption isotherm and effect of pH on absorption capacity also have been briefly reviewed.

Evaluation of factors affecting the sorption of sulfur dioxide by FIBAN fibrous anion exchangers

The sorption of sulfur dioxide from the air by the fibrous anion exchangers containing amino groups of different structure and basicity has been comparatively investigated. The most effective sorbents of sulfur dioxide are the anion exchangers with ternary amino groups, which have a high exchange capacity (more than 5 meq/g) and additionally contain secondary amino groups. The anion exchangers with high-base amino groups absorb sulfur dioxide at low relative humidity (30 %) but have low dynamic sorption capicity (up to 1.3 meq/g). The anion exchangers with primary and secondary amino groups absorb sulfur dioxide at high relative humidity (more than 54 %) if their cation exchange capacity is several times less than the anion exchange capacity.

Concentration affects significantly the capacity of biochar to adsorb nitrogen from forest runoff water

<p>In boreal peatland forests, drainage and harvesting increase nitrogen (N) export to watercourses and the highest N concentration in runoff water occurs outside the growing season when traditional water protection methods based on biological activity are inefficient. In these conditions, water purification based on adsorption could offer a solution. Biochar can be an effective sorbent material for removal of nutrients from water due to its high specific surface area, porous structure and high cation and anion exchange capacity. We tested adsorption capacity for total N (TN) of spruce and birch biochar using water collected from ditch drains of boreal harvested peatland. The water was collected outside the growing season when TN concentration was 4.6 mg L<sup>-1</sup>. During the growing season, TN concentration varies from 0.5 to 2 mg L<sup>-1</sup>. To study the effect of TN concentration on adsorption capacity, we diluted water samples to concentrations 1, 2, 3 and 4 mg L<sup>-1</sup>. We added 5 g of biochar to 1 L of water and shook the samples for 180 h. TN adsorption capacity increased monotonously from the smallest to the highest concentration. Adsorption capacity was 2.6 and 3.7 times greater in the highest concentration compared to the lowest concentration in spruce and birch, respectively. This indicates that concentration affects significantly the capacity of biochar to adsorb N from forest runoff water. Therefore, biochar can be an effective water protection tool in areas, which have high TN concentration, and it can be a complementary method supporting water purification outside the growing season.</p>

Karakteristik Muatan dan Sifat Fisikokimia Tanah pada Ultisol dan Andisol di Lahan kering Aceh Besar

Abstrak. Penelitian ini bertujuan untuk mengkaji karakteristik muatan dan sifat fisikokimia tanah pada Ultisol dan Andisol di lahan kering di Aceh Besar dengan menggunakan metode deskriptif pada jenis tanah Ultisol yang berasal dari Jantho dan Andisol dari Saree. Parameter yang di analisis yaitu kadar air, tekstur, pH, kapasitas tukar kation (KTK), kation dapat dipertukarkan (Ca-dd, Mg-dd, K-dd, Na-dd), kejenuhan basa, kapasitas tukar anion (KTA), C-organik, kemasaman dapat dipertukarkan (Al dan H), pH0, P-retensi dan pH NaF. Hasil penelitian menunjukan bahwa Ultisol dan Andisol di lahan kering Aceh Besar termasuk kedalam liat aktifitas rendah (LAR) yang ditandai dengan KTK efektif 12 cmol kg-1. Karakteristik muatan pada Ultisol Jantho dan Andisol Saree mempunyai muatan neto negatif dan bermuatan variabel. Penurunan C-organik dengan bertambahnya kedalaman tanah pada Ultisol dan Andisol diikuti oleh penurunan pH0, P-retensi, dan Al-dd. Upaya untuk meningkatkan muatan negatif pada Ultisol dan Andisol yaitu dengan meningkatkan pH atau menurunkan muatan titik nol tanah melalui pemberian bahan organik atau bahan yang mempunyai pH0 yang rendah seperti kompos, terak baja, batuan fosfat, bokashi sekam padi, dan abu terbang batubara. Characteristics of Charge and Soil Physicochemical Properties of Ultisol and Andisol in Dry land of Aceh BesarAbstract. This study aims to examine the characteristics of charge and physicochemical properties of Ultisol and Andisol in dry land of Aceh Besar using descriptive methods in Ultisol from Jantho and Andisol from Saree. Parameters analyzed are water content, texture, pH, cation exchange capacity (CEC), exchangeable cations (Ca-dd, Mg-dd, K-dd, Na-dd), base saturation, anion exchange capacity (AEC), C-organic, acidity exchangeable (Al and H), pH0, P-retention and NaF pH. The results showed that Ultisol and Andisol in dry land of Aceh Besar included in the low activity clay (LAC) characterized by effective CEC 12 kg-1. Characteristics of charge in Ultisol Jantho and Andisol Saree have a negative charge and variable charge. Decrease in C-organic by increasing the depth of soil in Ultisol and Andisol followed by decreased pH0, P-retention, and Al-dd. Efforts to increase the negative charge on Ultisol and Andisol by increasing the pH or decreasing the zero point of charge of the soil through giving of organic matter or materials that have a low pH0 such as compost, steel slag, rock phosphate, Bokashi rice husk and coal fly ash.

Production of Zeolite Sorbents from Burning and Co-burning Biomass with Coal

The limited resources of natural zeolites make it necessary to search for and use synthetic products. This paper presents a method of producing zeolite sorbents resulting from hydrothermal synthesis in an autoclave. The raw materials used in the syntheses were fluidized-bed fly ashes derived from the burning of forest biomass and sunflower hulls and two fly ashes derived from biomass combustion. The raw materials and zeolite sorbents were characterised using the analysis methods of phase composition and textural properties of the samples. The sorptive capacity of the raw materials and zeolite sorbents was determined by means of cation and anion exchange capacity. The analyses and research have shown that as a result of the synthesis process it is possible to obtain the following zeolite phases: sodalite, faujasite, chabazite. The determined value of the cation and anion exchange capacity for synthetic zeolite sorbents are greater than those which characterise natural zeolites.