Wyniki wyszukiwania - BazTech

1

Synthesis of Analcime Zeolite Using Al and Si from Waste Resources for the Removal of Pb/Cd Ions from Aqueous Solution

Kang Yubin, Im Byoungyong, Choi Jin-Ju, Yoon Jin-Ho, Kim Dae-Guen

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 1

67--72

EN

Zeolites, minerals with the formula Mx/n[AlO2]x(SiO2)y] zH2O, are environmentally friendly materials used as water treatment adsorbents, gas adsorbents, and petrochemical catalysts. This study used a mixture of aluminum black dross and waste glass to synthesize zeolites via a hydrothermal synthesis and analyzed the effects of varying reaction time on phase changes under different synthesis conditions. With increased reaction times, a phase change from zeolite Na-P1 to analcime was observed; on employing hydrothermal synthesis at 150°C for 96 h, the majority of the crystalline structures changed into analcime. Heavy metal cation adsorption was tested to assess the applicability of the synthesized analcime to water treatment. Zeolite adsorption of at least 95% was observed for both Pd and Cd ions. Although a higher level of adsorption was observed for Pb ion than Cd ion, Cd ion was demonstrated to undergo relatively faster adsorption when tested under optimal pulp density at the same level of adsorption (95%).

2

Heavy Metals Removal from Simulated Wastewater using Horizontal Subsurface Constructed Wetland

M-Ridha Mohanad J., Zeki Suhair L., Mohammed Sabah J., Abed Khalid M., Hasan Hassimi Abu

Journal of Ecological Engineering

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2021

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Vol. 22, nr 8

243--250

EN

This study aimed to assess the efficiency of Nerium oleander in removing three different metals (Cd, Cu, and Ni) from simulated wastewater using horizontal subsurface flow constructed wetland (HSSF-CW) system. The HSSF-CW pilot scale was operated at two hydraulic retention times (HRTs) of 4 and 7 days, filled with a substrate layer of sand and gravel. The results indicated that the HSSF-CW had high removal efficiency of Cd and Cu. A higher HRT (7 days) resulted in greater removal efficiency reaching up to (99.3% Cd, 99.5% Cu, 86.3% Ni) compared to 4 days. The substrate played a significant role in removal of metals due to adsorption and precipitation. The N. oleander plant also showed a good tolerance to the uptake of Cd, Cu, and Ni ions from water. The highest removal of the heavy metals indicated that the HSSF-CW would be a promising technology for heavy metal contaminated wastewater as well as in electroplating and manufacturing industries.

3

Zastosowanie soli sodowej kwasu N,N-bis(karboksymetylo)glutaminowego w procesie usuwania jonów metali z roztworów wodnych

Pańczuk-Figura I., Kołodyńska D., Rusek P., Hubicki Z.

Przemysł Chemiczny

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2015

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T. 94, nr 3

348-352

PL

Przedstawiono wyniki badań dotyczących wykorzystania kwasu N,N-bis(karboksymetylo) glutaminowego jako biodegradowalnego czynnika kompleksującego w procesie usuwania jonów metali z roztworów wodnych.

EN

Cu²⁺ and Pb²⁺ ions were complexed with Na N,N-bis(carboxymethyl) glutamate in aq. soln. and removed by sorption on 3 com. ion-exchange resins at pH 4–8.5 for 1–180 min. The sorption kinetics was described by the pseudo-second order model. The best ion-exchange resin showed a capacity 179.4 mg/g for Cu²⁺ and 184.96 mg/g for Pb²⁺ ions.

4

Equilibrium and kinetic studies on the removal of heavy metal ions with natural low-cost adsorbents

Varank G., Demir A., Bilgili M. S., Top S., Sekman E., Yazici S., Erkan H. S.

Environment Protection Engineering

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2014

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Vol. 40, nr 3

43--61

EN

Adsorption isotherms and kinetics of the removal of heavy metal ions (Ni, Pb, Zn) from aqueous solutions by natural adsorbents (zeolite, bentonite, clay) were investigated in a lab-scale batch study. The effect of various parameters such as adsorbent dosage, initial concentration of heavy metal ions, temperature, and agitation time were studied to optimise the conditions. Under those optimized conditions (180 rpm agitation rate, 120 min agitation time, pH 4.0, 298 K, 100 mg/dm3 initial adsorbate concentration), the removal percentages of heavy metal ions for natural adsorbents have been determined. The adsorption mechanisms and characteristic parameters of the process were analyzed by two and three parameter isotherm models (Langmuir, Freundlich, Temkin, Redlich-Peterson, Toth and Sips), and kinetic models (Lagergren's pseudo-first order, Ho and McKay's pseudo-second order). Adsorption thermodynamics of heavy metal ions (changes of standard enthalpy, entropy and free energy) on zeolite, bentonite and clay were also studied at 298,318 and 338 K.

5

Accumulation of mercury in the biomass of selected pleustophytes

Sitarska M., Traczewska T. M., Stanicka-Łotocka A., Filyarovskaya V., Zamorska-Wojdyła D.

Environment Protection Engineering

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2014

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Vol. 40, nr 1

165--174

EN

Application of phytoremediation process for the purification of the environment, particularly of surface water (running or standing) may be a future alternative to existing standard purification methods, in particular for heavy metal removal. Numerous hyperaccumulators are known which can be used for the purification of water, soil or sediment such as Salvinia or Lemna lemnids, occurring in temperate climates, and thus on the territory of Poland. Ability of mercury accumulation by Salvinia natans and Lemna minor was analyzed. The phytoremediation ability of lemnids was compared depending on their origin - commercial (artificial) cultures and those obtained from the natural environment. Phytoremediation process was carried out for a period of 14 days for the concentration of 0.15 mg Hg/dm3 and 0.2 mg Hg/dm3. It was found that both Salvinia natans and Lemna minor show a significant increase in biomass in the presence of mercury, even up to 76% for Lemna minor and 40% for Salvinia natans. The result of this increase was incorporation a considerable amount of mercury in the tissues of plant. The quantity of mercury in plants biomass was in the range of 41.16-115.28 mg Hg/kg DM, while in the control samples - only 0.2-0.6 mg Hg/kg DM.

6

Zeolitic adsorbent synthesized from powdered waste porcelain, and its capacity for heavy metal removal

Wajima T., Ikegami Y.

Ars Separatoria Acta

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2006

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No. 4

86-95

EN

A zeolitic adsorbent was synthesized from powdered waste porcelain kept at 80 °C for 24 h. The product contained the zeolite phases Na-P1 and hydroxysodalite. The product with the highest cation exchange capacity (CEC) was synthesized using 4 M NaOH and the sample weight / volume of alkali solution ratio was 1/4. The highest CEC obtained for the product was almost 1900 mmol/kg, which is the same as that of natural zeolite. The product with the highest CEC was tested for its ability to remove heavy metals (Fe, Cu, Ni, Zn, Pb, Cd, Mn, Cr, Al, B, Mo) from an acidic solution (pH 2). The product can neutralize the acidic solution to almost pH 7, and the capacity of the product for the removal of heavy metals is higher than that of the natural zeolite, except for Mo and B.

7

Modelling of ion-exchange equilibria in three-component systems

Petrus R., Warchoł J.K.

Chemia i Inżynieria Ekologiczna

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2004

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Vol. 11, nr 11

1193-1201

EN

Quatemary ion exchange equilibria have been studied between heavy metal solutions (Pb2+, Cd2+ and Cu2+) and the Na-fonn of clinoptilolite. The value of the ion-exchange equilibrium constant was estimated for the Langmuir, Competitive Langmuir, and thermodynamic isotherm models. For each isotherm, calculations were clone taking into account the concentration of ions in both phases. Additionally, for the thermodynamic isotherm, two other cases were considered: 1) activity of ions in liquid phase and concentration in solid phase, and 2) activity of ions in both phases. It was found that the exchange capacity for a given M2+ is not a constant value and may differ in one- or multi-component systems. The results show that the equilibrium model based on the law of mass action, which considers no-nideal behavior of both phases, allows us to best approximate real multi-component equilibrium data in all studied systems.

PL

W pracy przedstawiono modelowanie równowagi wymiany jonowej w układzie: trójskładnikowy roztwór metali (Pb2+, Cd2+, Cu2+) i klinoptylolit w formie Na. Wartości stałych równowagi wyznaczono z następujących równań: Langmuir, Competitive Langmuir (Nikolski) i izoterma termodynamiczna. Obliczenia na podstawie wymienionych równań przeprowadzono dla wartości stężeń jonów w obu fazach. Ponadto, dla izotermy termodynamicznej obliczenia przeprowadzono przy uwzględnieniu: (1) aktywności jonów w fazie ciekłej i stężeń jonów w fazie stałej oraz (2) aktywności jonów w obu fazach. Stwierdzono, że pojemność jonowymienna dla danego jonu metalu nie jest wartością stałą i może być różna dla układów jedno- i wieloskładnikowych. Uzyskane wyniki wskazują, że najdokładniejsze przewidywanie stężeń równowagowych we wszystkich rozpatrywanych układach trójskładnikowych uzyskano przy zastosowaniu modelu bazującego na prawie działania mas, który dodatkowo ujmował w swoim matematycznym zapisie nieidealne zachowanie jonów w obu fazach.