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Removal of copper from copper-contaminated river water and aqueous solutions using Methylobacterium extorquens modified Erzurum clayey soil

Celebi N., Nadaroglu H., Kalkan E., Kotan R.

Archives of Environmental Protection

2016

Vol. 42, no. 4

58--69

The objective of this study was to investigate the possibility of using natural and bacteria-modified Erzurum clayey soil with Methylobacterium extorquens as an alternative to high cost commercial adsorbent materials for the removal of copper from aqueous solution. The copper concentrations in the samples of the polluted river water and CuCl2 solutions treated by the natural and bacteria-modified Erzurum clayey soil (ECS) have been determined by spectrophotometric method. Firstly, the surface of ECS was modified with M. extorquens and surface functionality was increased. Then, the adsorption of Cu (II) from solution phases was studied with respect to varying metal concentration, pH, and temperature and agitation time. The maximum adsorption of Cu (II) for natural and bacteria-modified Erzurum clayey soil was observed at pH: 5.0. At different copper concentrations, copper adsorption analysis was performed on 1 g using clay soil or modified clay soil. Maximum adsorption of Cu (II) was obtained as 45.7 and 48.1 mg g-1 at initial concentration (50 mg/50 mL) and optimal conditions by natural and bacteria-modified clay soil, respectively. The copper concentration was decreased in the substantial amount of the leachates solutions of natural and bacteria-modified clay soil. Langmuir and Freundlich isotherms were used to describe the adsorption behavior of Cu (II) ions. The results showed that modified clay soil had a high level of adsorption capacity for copper ion. The various thermodynamic parameters such as ΔG°, ΔH° and ΔS° were analyzed to observe the nature of adsorption. The structural properties of the natural and bacteria-modified-ECS have been characterized by SEM, FTIR and XRD techniques. Consequently, it was concluded that the bacteria-modified clay soil could be successfully used for the removal of the copper ions from the aqueous solutions.

Adsorption of anionic dyes onto natural, thermally and chemically modified smectite clays

Kyzioł-Komosińska J., Rosik-Dulewska Cz., Pająk M., Krzyżewska I., Dzieniszewska A.

Polish Journal of Chemical Technology

2014

Vol. 16, nr 4

33--40

The aim of this study was to determine the adsorption capacity of the smectite clays (from the overburden of the lignite deposit in Belchatow) for two anionic dyes, i.e. Reactive Blue 81 (RB-81) and Direct Blue 74 (DB-74). Additionally, the infl uence of the thermal and chemical (acid and alkali) clay modifi cations on the amount of bonded dyes was investigated. The adsorption capacity of the clay (natural and modifi ed) was different for studiem dyes and depended on the initial concentration and modifi cation type. All the modifi ed clays adsorbed the dyes AT pH>pHPZC as the negatively charged surfaces of their particles (in accordance with the formula: AOH ↔ AO– +H+) prevented the formation of electrostatic bonds between the anionic dyes and the clay surface. The dyes were mainly bound with the hydrogen bonds forming between the donor groups in the dyes and the acceptor groups (–SiO and –Al2OH) in the clays. The coeffi cients in the adsorption isotherms were estimated with the linear and non-linear regression. The linear regression method was found that the Freundlich and Dubinin-Radushkevich isotherms described the dye sorption much better than the Langmuir model. On the other hand, all three models described well the experimental data in the non-linear regression method. Furthermore, the 1/n value (<1) obtained from the Freundlich equation for all the dye-sorbent systems indicated the favorable sorption.

Achievements and research tasks for poly(vinyl chloride) ageing and stabilization

Minsker K. S., Zaikov G. E., Kozłowski R., Kubica S.

Przetwórstwo Tworzyw

2010

[R.] 16, nr 2

69-84

Perspectives of PVC manufacture, not containing of labile groups in a backbone are considered. It will provide drastic increase of an intrinsic stability of polymeric products, possibility of PVC processing with the minimal contents or in total absence of stabilizers and other chemicals - additives and opportunity of creation of materials and products on a PVC basis with the essentially increased service life-time. Presented data allow to create rigid, semi-rigid and flexible (plasticized) materials and products with the minimal contents of chemicals - additives and increased life-time of their service at exploitation in natural and special conditions.

Rozważano perspektywy wytwarzania PVC niezawierającego nietrwałych grup w swojej strukturze. Omówiono znaczne zwiększenie stabilności produktów polimerowych, możliwość przetwórstwa PVC o minimalnej zawartości lub całkowitym braku stabilizatorów oraz innych środków pomocniczych, jak również możliwości stworzenia materiałów i wyrobów opartych na PVC o zasadniczo zwiększonym czasie eksploatacji. Przedstawione badania pozwalają na opracowanie sztywnych, półsztywnych i elastycznych (plastyfikowanych) materiałów i wyrobów o minimalnej zawartości środków pomocniczych oraz zwiększonym czasie eksploatacji w warunkach naturalnych oraz szczególnych.