Organic Sorbents Research Articles

1403 二塔循環式流動層における粉末有機系収着剤の収脱着特性(熱工学I)

1403 二塔循環式流動層における粉末有機系収着剤の収脱着特性(熱工学I)

Recovery of 131I and 137Cs from a solution simulating NPP trap waters

Sorption of 131I and 137Cs from a solution simulating NPP trap waters on various inorganic and organic sorbents was studied. The highest degree of 131I recovery (>99%) can be attained with Fizkhimin granulated sorbents based on coarsely porous silica gel containing Ag and Ni in 1: 4 ratio, with Kd for 131I exceeding 105 ml g−1 at V/m = 103 ml g−1 and contract time of the solid and liquid phases of 120 min. Elevation of the solution temperature to 40°C does not affect the degree of 131I and 137Cs recovery. The degree of 137Cs recovery in all the experiments did not exceed 35%. The degree of 131I recovery by coprecipitation with AgCl and Ag4[Fe(CN)6] was about ∼96% and only 65%, respectively.

Polymerin and Lignimerin, as Humic Acid-like Sorbents from Vegetable Waste, for the Potential Remediation of Waters Contaminated with Heavy Metals, Herbicides, or Polycyclic Aromatic Hydrocarbons

Polymerin is a humic acid-like polymer, which we previously recovered for the first time from olive oil mill waste waters (OMWW) only, and chemically and physicochemically characterized. We also previously investigated its versatile sorption capacity for toxic inorganic and organic compounds. Therefore, a review is presented on the removal, from simulated polluted waters, of cationic heavy metals [Cu(II), Zn, Cr(III)] and anionic ones [Cr(VI)) and As(V)] by sorption on this natural organic sorbent in comparison with its synthetic derivatives, K-polymerin, a ferrihydrite-polymerin complex and with ferrihydrite. An overview is also performed of the removal of ionic herbicides (2,4-D, paraquat, MCPA, simazine, and cyhalofop) by sorption on polymerin, ferrihydrite, and their complex and of the removal of phenanthrene, as a representative of polycyclic aromatic hydrocarbons, by sorption on this sorbent and its complexes with micro- or nanoparticles of aluminum oxide, pointing out the employment of all these sorbents in biobed systems, which might allow the remediation of water and protection of surface and groundwater. In addition, a short review is also given on the removal of Cu(II) and Zn from simulated contaminated waters, by sorption on the humic acid-like organic fraction, named lignimerin, which we previously isolated for the first time, in collaboration with a Chilean group, from cellulose mill Kraft waste waters (KCMWW) only. More specifically, the production methods and the characterization of the two natural sorbents (polymerin and lignimerin) and their derivatives (K-polymerin ferrihydrite-polymerin, polymerin-microAl(2)O(3) and -nanoAl(2)O(3), and H-lignimerin, respectively) as well as their sorption data and mechanism are reviewed. Published and original results obtained by the cyclic sorption on all of the considered sorbents for the removal of the above-mentioned toxic compounds from simulated waste waters are also reported. Moreover, sorption capacity and mechanism of the considered compounds on polymerins and lignimerins are evaluated in comparison with other known natural sorbents, especially of humic acid nature and other organic matter. Some of their technical aspects and relative costs are also considered. Finally, the possible large-scale application of the considered sorption systems for water remediation is briefly discussed.

1106 収着式冷凍機における収着剤塗布フィン付熱交換器の脱着挙動(熱工学I)

1106 収着式冷凍機における収着剤塗布フィン付熱交換器の脱着挙動(熱工学I)

Using lignimerin (a recovered organic material from Kraft cellulose mill wastewater) as sorbent for Cu and Zn retention from aqueous solutions

Adsorption of copper and zinc in lignimerin (an organic material mainly composed by lignin, carbohydrate fragments and some extractives) and its acid derivative ( H-lignimerin), recovered from Kraft cellulose mill wastewater was examined. A Box–Behnken experiment design, used to optimize lignimerin recovery process, revealed that the type of solvent used for precipitation is a determining factor in the amount of substance obtained. Conversely, batch adsorption studies at pH 4.0 revealed that the maximum adsorption capacities, modeled by the Langmuir equation, were 666.7 and 370.4 mmol kg −1 for Cu(II) and Zn(II), respectively in lignimerin and 232.6 and 312.5 mmol kg −1 for Cu(II) and Zn(II), respectively in H-lignimerin. The adsorption of Cu(II) and Zn(II) through deprotonated hydroxyl and carboxylic groups was the dominant mechanism that may explain the adsorption in both materials. The adsorption capacities indicated that lignimerin, with a molecular mass between 50 and 70 kDa, has a potential use as an organic sorbent for removing copper and zinc from liquid resources.

416 収着式冷凍機における有機系収着剤の収着挙動(熱工学III)

416 収着式冷凍機における有機系収着剤の収着挙動(熱工学III)

Adsorptive Characteristics of the Siloxane Surfaces of Reduced-Charge Bentonites Saturated with Tetramethylammonium Cation

To elucidate interactions of neutral organic contaminants (NOCs) with siloxane surfaces (often referred to hydrophobic nanosites)found between cations in 2:1 phyllosilicates, adsorption of aliphatic and aromatic compounds onto both internal and external siloxane surfaces oftetramethylammonium-intercalated bentonite with a cation exchange capacity (CEC) of 108 cmol/kg (108TMA) and its reduced-charge bentonite (CEC = 65 cmol/ kg, 65TMA) were investigated. Reduction of the layer charge and saturation of bentonite interlayers with TMA+ modify the interlayer microenvironments, which dramatically promote adsorption of NOCs. Specific mechanisms (i.e., steric restriction and phenyl-effect) control the adsorption of NOCs onto internal siloxane surfaces of TMA+ -bentonites from water. The adsorption sites of 108TMA can not provide sufficient space to accommodate NOCs, hence hindering adsorption. Adsorption mechanism on 65TMA varies with solute-loadings, from polarity-selective at low loadings to aromaticity-preferable at high loadings. Significant contribution of phenyl-effect between adsorbed-solutes to aromatics adsorption on 65TMA is found. Solvent polarity effect on the aggregation of TMA+ -bentonites and aniline adsorption demonstrated that the contribution of external siloxane surfaces to favor adsorption in n-hexane are actually exploited but generally omitted. These observations provide significant insights into distinguishing different uptake mechanisms as well as the potential means for the rational design of better organic sorbents.

An Experimental Investigation of Sorption Process in Fluidized Bed With Cooling Pipe

An experimental investigation of a fluidized bed with multiple cooling pipes was conducted to study adsorption characteristics of a new organic sorbent desiccant material (HU300P) for a new air conditioning system. The mass ratio of the present sorbent desiccant powder type is from 1.3 to 2.3 times greater than that of silica gel. The sorption rate of the water vapor in the sorbent bed was measured under various conditions. It was found that the sorption rate is highly dependent on the effect of cooling pipes. The sorption ratio increases and the completion time for the sorption process decreases by using multiple cooling pipes.

EFFECT OF SAND PARTICLE SIZE, OIL CONTAMINATION, AND WATER TABLE LEVEL ON THE EFFECTIVENESS OF SORBENTS IN WICKING OIL FROM CONTAMINATED WETLAND

ABSTRACT Oil spill cleanup in wetlands is problematic because of the limited remediation techniques that can be applied in such environments. The use of sorbents to clean up oil spills presents many advantages due to simplicity of approach and the inexpensive nature of these materials. Furthermore, sorbents can be used not only as wicking agents but also as microbial media that mediate hydrocarbon biodegradation. Once a sorbent is applied to an impacted wetland, it absorbs the contaminating oil. It retains the oil for a sufficient length of time to allow biodegradation of hydrocarbons by indigenous bacteria under aerobic conditions. In addition, plant-derived organic sorbents are biodegradable, thus leaving no permanent residue. Ammoniated bagasse is one of the biodegradable organic sorbents that contain nitrogen as a nutrient needed to support the activity of oil degrading bacteria. In this study, we evaluated the effectiveness of sorbents in wicking oil from the subsurface of oil-contaminated sediments under various conditions. Several microcosms were prepared to simulate saturated wetland environments. Glass cylinders, 10 cm in diameter and 10 cm in height, enclosed these microcosms. Each microcosm was layered in the following sequence (from the bottom to the top): a clean sand layer, an oiled-sand layer, and an overlying sorbent layer. Sand, sorbent, and water were sterilized prior to use to ensure that no biodegradation occurs during the experiment. The different conditions included: 2 particle sizes of sand (20 × 30 and 60 × 80 U.S. Mesh), 2 levels of oil contamination (25% and 75% of saturation), 3 water levels (at the oiled-layer/clean sand interface, at the oiled-layer/sorbent-layer interface, and at the sorbent-layer/air interface), and 2 levels of sorbent (presence or absence). Oil wicking experiments were performed in airtight microcosms for a period of 3 months. At the termination of an experiment, each layer of the microcosms was separated and samples were taken. Samples were extracted with dichloromethane and quantified by gas chromatography/mass spectrometry (GC-MS). Mass balances in each microcosm were established in terms of total petroleum hydrocarbons (TPH). TPH includes alkanes (C10-C35); pristane; phytane; hopane; 2-, 3-, and 4-ring PAHs; and pyrogenic PAHs (5- & 6-rings). The TPH change in each layer from time zero to 3 months was used to determine the effectiveness of the sorbent under each condition tested.

Modeling PAH mass transfer in a slurry of contaminated soil or sediment amended with organic sorbents

A three-compartment kinetic partitioning model was employed to assess contaminant mass transfer and intraparticle diffusion in systems comprising dense slurries of polluted soil or aquifer sediment with or without sorbent amendments to sequester polycyclic aromatic hydrocarbons (PAHs). The model was applied to simulate temporal changes in aqueous and particle-bound PAH concentrations comparing different pollution sources (heavy oil or tar sludge) and various sorbent amendments (polyoxymethylene (POM), coke breeze, and activated carbon). For the model evaluation, all the parameters needed were directly measured from a series of experiments, allowing full calibration and verification of model predictions without parameter fitting. The numerical model reproduced two separate laboratory-scale experiments reasonably: PAH uptake in POM beads and PAH uptake by semipermeable membrane devices. PAH mass transfer was then simulated for various scenarios, considering different sorbent doses and mass transfer rates as well as biodegradation. Such model predictions provide a quick assessment tool for identifying mass transfer limitations during washing, stabilization, or bioslurry treatments of polluted soil or sediment in mixed systems. It appears that PAHs would be readily released from materials contaminated by small oil droplets, but not tar decanter sludge. Released PAHs would be sequestered rapidly by activated carbon amendment but to a much lesser extent by coke breeze. If sorbing black carbon is present in the slurries, POM pellets would not be effective as a sequestration amendment. High first-order biodegradation rates in the free aqueous phase, e.g., in the order of 0.001 s −1 for phenanthrene, would be required to compete effectively with adsorption and mass transfer for strong sorbents.

Heat and mass transfer characteristics of organic sorbent coated on heat transfer surface of a heat exchanger

This paper describes heat and mass transfer characteristics of organic sorbent coated on heat transfer surface of a fin-tube heat exchanger. The experiments in which the moist air was passed into the heat exchanger coated with sorption material were conducted under various conditions of air flow rate (0.5–1.0 m/s) and the temperature of brine (14–20°C) that was the heat transfer fluid to cool the air flow in the dehumidifying process. It is found that the sorption rate of vapor is affected by the air flow rate and the brine temperature. Meanwhile, the attempt of clarifying the sorption mechanism is also conducted. Finally the average mass transfer coefficient of the organic sorbent coated on heat transfer surface of a fin-tube heat exchanger is non-dimensionalzed as a function of Reynolds number and non-dimensional temperature, and it is found that the effect of non-dimensional temperature on them is larger than Reynolds number .

Development of Engineered Natural Organic Sorbents for Environmental Applications. 4. Effects on Biodegradation and Distribution of Pyrene in Soils

The effects of engineered natural organic amendments on the biodegradation and distribution of pyrene in soils were assessed. Pyrene was aged for 105 days in soils amended with either raw or superheated water (SHW)-processed MI peat or soybean stalks, and then subjected to biodegradation with specifically selected microorganisms for 130 days. Initial rates of pyrene mineralization in the soils were increased by addition of raw MI peat, but markedly decreased by additions of SHW-processed MI peat and both processed and raw soybean stalks. Pyrene sorbed by the processed organic sorbents was, however, slowly but steadily degraded by microorganisms over a greater than 4-month test period. Pyrene distributions in the soils were examined by sequential extractions of samples before and after biodegradation. Fractions of pyrene extracted readilywith water or water/methanol mixtures were decreased substantially in both soils bythe addition of processed amendments, while the nonextractable fractions associated with humic and fulvic acids and humin were increased markedly. The results demonstrate that SHW-processed amendments effectively reduce the ecological and human availability and aqueous phase extractability of organic contaminants while facilitating their steady microbial degradation and eventually complete remediation.

Treatment of tunnel wash waters — experiments with organic sorbent materials. Part II: Removal of toxic metals

In the first part of the article, the column and the bag experiments concerning removal of polycyclic aromatic hydrocarbons (PAHs) and nonpolar oil (NPO) from tunnel wash waters using organic sorbent materials have been described. This part presents the results of removal of toxic metals. The metals of concern (Al, As, Cd, Cr, Cu, Fe, Pb, Mo, Ni, and Zn) were selected based on the priority toxicant pollutants defined in surface water quality criteria. Concentrations of these metals in the collected effluents varied more than the concentrations of PAHs and NPO, and thus only metal contents were considered for statistical analyses. These analyses determined significant differences (P < 0.05, P < 0.01, and P < 0.001) between the mean metal concentrations in the column effluents and those in applied wash water of road tunnel. The results obtained during both experiments revealed that the organic sorbents, and in particular their combination, removed toxic metals more effectively from wash water of road tunnel than from wash water of tunnel electrostatic filters. Among the investigated toxicants, Al and Fe showed the highest levels of reduction in the column experiment, 99.7% and 99.6%, respectively. The lowest reduction levels of 66.0% and 76.2% were found for Pb and Mo, respectively. The results of the bag experiment showed that even one day treatment of wash waters from tunnel electrostatic filters could reduce concentration of some toxicants by more than 70% (Al and Fe) and 80% (Cu).

605 収着剤冷凍機における熱交換器に塗布した収着剤の収・脱着挙動(熱工学I)

605 収着剤冷凍機における熱交換器に塗布した収着剤の収・脱着挙動(熱工学I)

606 収着剤デシカントロータと圧縮式冷凍機による複合式空調システム(熱工学I)

606 収着剤デシカントロータと圧縮式冷凍機による複合式空調システム(熱工学I)

Treatment of tunnel wash waters – experiments with organic sorbent materials. Part I: Removal of polycyclic aromatic hydrocarbons and nonpolar oil

Tunnel wash waters characterize all waters that run off after washing procedures of tunnels are performed. These waters represent a wide spectrum of organic and inorganic pollutants, such as polycyclic aromatic hydrocarbons (PAHs) and toxic metals. Removal of such contaminants from water runoff was investigated using laboratory tests after washing procedure was performed on two road tunnels in eastern Norway (Hanekleiv and Bragernes). Due to diverse character of both, treatment media and treated wash waters, the whole investigation was divided into two separate laboratory experiments. The treatment efficiencies were established based on the levels of concentrations and reductions of the measured contaminants in the effluents released from the tested media. In the first part of the article, the contents of nonpolar oil (NPO), 16 individual PAHs, and total PAHs are described. This part revealed that the combination of two organic sorbent materials provided the highest treatment efficiency for wash waters released from the road tunnel and from electrostatic filters. The greatest reduction levels reached 97.6% for NPO, 97.2% for benzo[a]pyrene, and 96.5% for the total PAHs. In the second part of the article, the concentrations and the removal rates of toxic metals are reported.

Sorption Characteristics of Organic Sorbent Coated on Heat Transfer Surface of a Heat Exchanger Under the Low Temperature

Sorption Characteristics of Organic Sorbent Coated on Heat Transfer Surface of a Heat Exchanger Under the Low Temperature

Sorption-Desorption Processes of Metals and Metalloids in Soil Environments

Trace elements may be present in solution with positive or negative charges and in different redox state. They occur predominantly in cationic form (Pb, Cu, Zn, Ni, Cd, Hg, Cr(III), Co) but some trace elements are present in anionic form (As, Se, Cr(VI), Mo and B). In soil environments, sorption/desorption reactions on/from inorganic and organic sorbents control the concentration of metals and metalloids in solution and affect their bioavailability, leaching and toxicity. Sorption-desorption processes of elements in cationic form differ greatly from those in anionic form. These reactions are affected by many factors, such as pH, nature of the sorbents, presence and concentration of organic and inorganic ligands, including humic and fulvic acids, root exudates and nutrients. Furthermore, redox reactions, both biotic and abiotic, are of great importance in controlling the oxidation state and thus, the mobility, the phytoavailability and the toxicity of many elements, such as Cr, Se, Co, Pb, As, Ni and Cu (Kabata-Pendias, 2001; Huang and Germida, 2002; Violante et al., 2002; Sparks, 2003; Huang and Gobran, 2005; Violante et al., 2007). The aim of this presentation is to provide information on the factors which affect the mobility of trace elements. Special attention is devoted to the influence of inorganic and organic ligands, including nutrients and root exudates, on the sorption/desorption processes of trace elements in cationic and anionic forms on/from soil components, soils and selected synthetic minerals (double layered hydroxides, the so called “anionic clays”). The soil components responsible for trace element sorption include, soil humic substances, phyllosilicates, carbonates and variable charge minerals (constituents such as Fe, Al, Mn and Ti oxides, short-range ordered aluminosilicates as well as phyllosilicates coated by OH-Al or OH-Fe species whose charge varies with the pH of the soil solution). Recently, evidence on the sorption of heavy metals on microorganisms have been reported (Jackson, 1998). Soil components differ greatly in their sorption capacities, their cation and anion exchange capacities, and the binding energies of their sorption sites. Trace element sorption kinetics depend on the type of surface and trace element, but generally are rapid. Half times for bivalent cations, such as Pb, Zn, Cu and Cd, sorption on peat range from 5 to 15 seconds. Except for some noncrystalline minerals that have very high specific surface charge density with highly reactive sites, humic substances appear to have the greatest capacity for sorption of trace elements in cationic form. A body of evidence has demonstrated that humic matter and metal oxides are much more effective scavengers of trace elements in cationic form, than even the most efficient sorbent among phyllosilicates, indicating that specific sorption and other complexation processes are the dominant binding mechanisms (Jackson, 1998; Huang and Germida, 2002; Spark, 2003). Complexation reactions have the following effects: i) metal ions are prevented from being precipitated; ii) complexing agents can act as carriers for trace elements in soil solution; iii) their toxicity is often reduced by complexation.

Sorption Characteristics of Organic Powder Sorption Material in Fluidized Bed with a Cooling Pipe

The dynamic sorption characteristics of organic sorbent materials have been studied by using fluidized bed with a cooling pipe. The organic powder type sorbent made from a bridged complex of sodium polyacrylate which is one of the sorption polymers is adopted in this study. Sorption rate of water vapor and the variation of temperature in the sorbent bed with time were measured under various conditions. As a result, sorption ratio increases and the completion time for the sorption process decreases by using a cooling pipe. Furthermore, the non-dimensional correlation equations were obtained for water vapor mass transfer under sorption process in terms of relevant non-dimensional parameters.

Thermochemical aspects of interaction of polyimide composites with organic sorbents

Interaction of ITA-31 polyimide binder with a series of industrial sorbents based on styrene and vinylpyridine derivatives was studied.