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Soft Ion Divalent Metals toward Adsorption on Zn/Al-POM Layered Double Hydroxide

Silaen Luna, Elfita, Mohadi Risfidian, Normah, Juleanti Novie, Palapa Neza Rahayu, Lesbani Aldes

Journal of Ecological Engineering

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2021

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Vol. 22, nr 10

109--120

EN

Development of Zn/Al layered double hydroxide by intercalation using polyoxometalate (POM) K4 [α-SiW12O40] to Zn/Al-POM was investigated. The success of the modification is evidenced by the XRD, FT-IR, and BET characterization data. XRD characterization showed an increase in the interlayer distance from 8.59 Å in Zn/Al LDHs to 10.26 Å in Zn/Al-POM. This success is also supported by the FT-IR data with the appearance of vibrations around 779–979 cm-1 which indicates the vibration of the polyoxometalate compound in Zn/Al-POM. Other supporting data in the form of BET also prove an increase in surface area from 1.968 m2/g in Zn/Al LDHs to 14.042 m2/g Zn/Al-POM. The ability of Zn/Al-POM as an adsorbent is proven through several parameters such as kinetics, isotherm, thermodynamics, and regeneration for Cd2+, Pb2+, Ni2+, and Co2+. Adsorption kinetics showed that Zn/Al-POM was more likely to follow the pseudo-second-order adsorption kinetics model for Cd2+, Pb2+, Ni2+, and Co2+. The results of determining the adsorption isotherm parameters of Zn/Al-POM tend to follow the Freundlich isotherm model with a maximum adsorption capacity of 74.13 mg/g on Pb2+. The regeneration process showed that Zn/Al-POM was more resistant than Zn/Al LDHs up to 3 cycles. It was proven that Zn/Al-POM was able to survive in the last cycle up to 69.19% on Ni2+.

2

High Structural Stability and Adsorption Capacity of Zn/Al-Biochar and Cu/Al-Biochar Toward Adsorption of Cr(VI)

Palapa Neza Rahayu, Taher Tarmizi, Siregar Patimah Mega Syah Bahar Nur, Normah, Juleanti Novie, Wijaya Alfan, Badri Arini Fousty, Lesbani Aldes

Journal of Ecological Engineering

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2021

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Vol. 22, nr 4

213--223

EN

Layered double hydroxide (LDH) Zn/Al and Cu/Al was synthesized by using the coprecipitation method under base condition at pH 10 following with formation of composites based on biochar (BC) to form Zn/Al-BC and Cu/ Al-BC. The materials were characterized by XRD, FTIR, BET, and thermal analyses. Furthermore, materials was applied as adsorbent of Cr(VI) on aqueous solution. The performance of composites as adsorbent was evaluated by reusability of adsorbent toward Cr(VI) adsorption process. The results showed that Cu/Al-BC and Zn/Al-BC can reuse the re-adsorption process with the adsorption ability of more than 60%. The adsorption capacity of Cu/ Al-BC and Zn/Al-BC was higher than that of starting materials and up to 384.615 mg/g for Cu/Al-BC and 666.667 mg/g for Zn/Al-BC. Both composites showed the potential adsorbents to remove Cr(VI) from aqueous solution.

3

Competitive Removal of Cationic Dye Using NiAl-LDH Modified with Hydrochar

Normah, Palapa Neza Rahayu, Taher Tarmizi, Mohadi Risfidian, Arsyad Fitri Suryani, Priambodo Aldi, Lesbani Aldes

Ecological Engineering & Environmental Technology

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2021

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Vol. 22, iss. 4

124--135

EN

In this study, NiAl-LDH was modified with hydrochar using the NiAl-Hydrochar composite coprecipitation method. Materials were characterized by XRD and FT-IR analysis. XRD diffractogram and FT-IR spectra show that the NiAl-Hydrochar composite material has the characteristics of the precursors. NiAl- Hydrochar composite materials have a large adsorption capacity to adsorb cationic dyes. The adsorption follows the Langmuir adsorption isotherm model with the maximum capacity (Qmax) of the NiAl-Hydrochar composite material reaching 256.410 mg/g for malachite green and the adsorption process takes place spontaneously and endothermically. The regeneration process of NiAl-Hydrochar composites was more stable and the decrease was not significant (>70%). The selectivity of the dye mixture showed that the adsorbent was more selective for malachite green dye compared to methylene blue and rhodamine-B.