Papers by Keyword: Adsorbent

Abstract: Pumped groundwater in the lignite open-cast mines in Lusatia, Germany, contains a high level of ferrous iron (up to 1000 mg/L) at an initial pH of about 5. In recent R&D projects G.E.O.S. developed an innovative water treatment process for ferrous iron oxidation using the autochthonous microbial consortium in the mine water. The pilot plant is operated in the Nochten open-pit mine in cooperation with the LEAG and produces 5 – 10 t of schwertmannite per year. Extensive research work was carried out in parallel to utilize the produced schwertmannite. Pigment production proved to be technically feasible but difficult due to economic and market constraints. However, the high affinity of schwertmannite to oxy-anions provides the suitability for utilization as adsorbent to remove arsenate, antimonate, chromate, molybdate, vanadate or phosphate from mine water or industrial effluents. In the R&D project SURFTRAPII two kinds of filter-stable sorption materials were developed 1) by compacting schwertmannite or 2) by adhesive curing using an organic polymer, respectively. The produced filter-stable adsorbents were tested under technical conditions in cooperation with potential end users to remove arsenate, molybdate and phosphate from mine and industrial water and to concentrate valuable metals. The results showed a better performance of the material compared to other commercially available iron hydroxide adsorbents.

Abstract: This research investigates the use of charcoal produced from waste peels of the mangosteen (Garcinia mangostana L.) fruit as adsorbents of lead contaminants for cost effective wastewater treatment. Test solutions of lead (Pb (NO₃)₂) were prepared over 0.003 M to 0.5 M, to observe a color change KI was added to the solution. Charcoal from mangosteen peel was added in powder form or as flakes. We found that at least 1.5 g of charcoal was required to adsorb lead from 20 ml of a 0.015 M (Pb (NO₃)₂) solution, as indicated by low sediment and reduced color change.

Abstract: The article gives considerations to issues dealing with systems for separation and purification of gas mixtures containing methane. A method of pressure swing adsorption is suggested for biogas purification. The present results show the use of natural zeolite (Izhberdinskoye field, Orenburg region) to improve biogas quality by adsorption of water vapor, hydrogen sulphide and carbon dioxide.

Abstract: Ferric oxide nanoparticles are environmentally benign and can be selective toward lead, especially in neutral to mildly alkaline pH of groundwater. However, due to very fine particles and low mechanical strength, it prevents these materials to apply in point of use filter or large scale fixed-bed adsorption. In this study, polymeric gel cation exchanger, Purolite C100, supported ferric oxide nanoparticles, C100-Fe, was synthesized, characterized, and tested with challenging water according to NSF standards 53. From SEM-EDX studies, it can imply that high concentration of iron can be doped and distributed within the gel phase structure of the C100 approximately 22% by mass. The TEM micrographs confirm the size of hydrated ferric oxide fall into the nanometer range about 10-60 mm. The fixed-bed adsorption experiments demonstrated that C100-Fe can remove lead below the stringent standard of 0.05 mg/L up to 15,000 BVs, whereas the GAC, GAC-Fe, and C100 can treat the same test water only 1200, 1700, and 3500 BVs, respectively. The results confirm that C100-Fe can be efficiently substituted to the traditional GAC for lead removal in drinking water.

Abstract: This study is aimed to synthesize, characterize and validate the performance of a novel hybrid nanoadsorbent for selective removal of lead from a battery manufacturing wastewater. The hybrid nanosorbent, named as HCIX-Fe, was prepared by impregnating hydrated Fe (III) oxide (HFO) nanoparticles inside polymeric cation exchange resin containing negatively charged sulfonic acid (-SO₃^-) fixed functional groups. HCIX-Fe was characterized by SEM-EDX and XRD to confirm the distribution and determination of phase of HFO dispersed inside the hybrid nanosorbent. Fixed-bed column runs with HCIX-Fe beads were carried out using wastewater from a battery manufacturing plant. The wastewater had a pH of 1.8 and contained of 3.5 mg/L of Pb²⁺ coexisted with 250 mg/L Ca²⁺ ions. The results have shown that HCIX-Fe column could treat lead-contaminated water up to 6,500 bed volumes (BVs) before the occurrence of breakthrough concentration of 0.2 mg/L Pb²⁺ resulting in a removal capacity of 6.85 mg Pb²⁺/ml of the HCIX-Fe bed. Under similar condition, adsorbent columns with cation exchange resin (C100), granulated activated carbon (GAC) and granulated activated carbon impregnated with HFO (GAC-Fe), could treat the same wastewater only until 400, 900 and 1,500 BVs, respectively. When compared with the parent adsorbents, impregnation by HFO greatly enhanced the Pb²⁺ removal capacity of C100 and GAC by 1,625% and 167%, respectively. Both HFO and high density of sulfonic acid (-SO₃^-) in the host cation exchanger are individually capable of selective removal of Pb²⁺ ions; however the hybrid material demonstrated a synergistic effect for Pb²⁺ removal through the Donnan Membrane effect. Due to amphoteric behavior of HFO, the HCIX-Fe could be regenerated and reused with 10 BVs of 2% HNO₃ and 1% FeCl₃·6H₂O solution.

Abstract: The objective of this study was to prepare adsorbents from two kinds of oily sludge and evaluate their adsorption characteristics. The results showed that the optimum conditions of adsorbent made from JL sludge was using ZnCl₂ as activator, the concentration of activator was 0.5mol/L, solid-liquid ratio was 1:2, pyrolysis temperature was 550°C, staying time was 2h. The optimum conditions of adsorbent made from LH sludge was pyrolysis directly. Pyrolysis temperature was 650°C, staying time was 2h. The surface morphologies of two adsorbents were relatively rough and had irregular porous structure mainly in mesoporous. The iodine adsorption values of two adsorbents can reach 451.22mg/g and 376.48mg/g and the oil removal rate of simulated wastewater can reach 91.47% and 92.28% respectively.

Abstract: This study examines the ability of nanozeolite-geopolyme ras adsorbent material for motor vehicle emissions. There were three samples that have been synthesized by varying metakaolin and rice husk ash masses. Nanozeolite-geopolymer samples were synthesized through geopolymerization method at 70°C by mixing metakaolin with rice husk ash and activated with NaOH solution. Samples were recurring at 200°C to improve the crystalline level. Based on the XRD characterization of the three samples, two of them contain zeolite X, namely ZG_A (100% metakaolin, ASP 0%) and ZG_B (metakaolin: ASP, 2: 1). However, zeolite X phase most conceived by ZG_A. Therefore, the ZG_A sample was then used as adsorbent to absorb motor vehicle exhaust. The tests were performed four times with time variation of 10, 20, 30, and 40 minutes. The XRD results showed that the material was successfully absorbed lead oxide, manganese oxide and phosphorus which are hazardous compounds when inhale by human being.

Abstract: The aim of this work was to study the adsorption efficiency of chitosan as an adsorbent for triclosan, commercially known as Irgasan, in aqueous solutions. The effects of contact time, pH and temperature were investigated using a batch adsorption technique. Langmuir and Freundlich isotherms were used to analyze the equilibrium data at different absorption conditions. The results showed that the maximum adsorption capacity for chitosan was found in the acidic pH 3 and at a temperature of 65 oC. These results suggested that chitosan can be used as an adsorbent for removal of triclosan from aqueous solutions.

Abstract: Iron oxide (α-Fe2O3) as adsorbent was no longer new in CO2 adsorption studies. However, its contributions in the industry still in limited wherein lack of convincing results of quantifying of adsorbed CO2. This work presents an analysis for α-Fe2O3 was prepared by simple mixing method with identified the adsorption capacity that applied in CO2 capture. The synthesized α-Fe2O3 from different concentrations of precursor were analyzed using XRD, N2 adsorption-desorption isotherms with BET and BJH method, TEM, FTIR, CO2 adsorption at 298 K, CO2-TPD and TGA-DTG. It was noted that 2M concentration of precursor (s2M) with highest crystallite peaks shows highest surface area among all samples which indicative of well generated pores. The different concentration of precursor was found generated more porosity rather than particle size according to TEM micrograph. The sphere shape crystallite particle with high surface area (50.5 m2/g) and porosity were desirable properties in CO2 adsorption. Consequently, physically adsorbed CO2 with adsorption at 298 K was highest with adsorption capacity of at 17.0 mgCO2/gadsorbent. Finally, chemically adsorbed CO2 was successfully identified from CO2–TPD analysis with adsorption capacity of 0.19 mgCO2/gadsorbent and 1.31 mgCO2/gadsorbent at maximum desorption temperature of 375 °C and 749 °C respectively.

Abstract: Prussian blue analogue nickel ferrocyanide (NiPB) decorated carbon nanotube sponge (CNT sponge) was prepared as a newly designed spongiform adsorbent. This composite material was characterized by scanning electron microscopy (SEM), inductively coupled plasma (ICP) and tested in adsorption experiments. Results show that the CNT-NiPB sponge was equipped with large holes and porous structure, a large number of MWNTs and NiPB particles uniformly deposited on the surface and internal cavities. This adsorbent CNT-NiPB sponge showed a good adsorption selectivity of cesium and strontium in mixed aqueous solution, which is mainly induced by the ion exchange reaction of NiPB and metal ions. The novel spongiform adsorbent might have a promise prospect in radioactive wastewater treatment applications.