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Synthesis and Characterization of Zinc Oxide-Zeolite Photocatalyst Nanocomposite for Heavy Metals Degradation

Agustina Tuty Emilia, Ramadhini Tri Karimah, Melwita Elda, Bahrin David, Wijayanti Maria Siswi, Gayatri Rianyza

Journal of Ecological Engineering

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2024

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Vol. 25, nr 3

272--281

EN

Heavy metals are the major contributors to pollution due to their enduring presence and poisonous characteristics. Wastewater that contains heavy metals is classified as harmful and has the potential to contaminate the environment. Large-scale disposal of heavy metal discharged into the environment causes significant environmental harm. Commonly seen heavy metals in water deposits include non-biodegradable metals such as cadmium (Cd), copper (Cu), lead (Pb) and iron (Fe). To mitigate the adverse effects of environmental contamination, it is necessary to handle wastewater containing heavy metals properly and optimally. Photocatalysis is a technology that involves the breakdown of pollutants with the use of light. This study aims to synthesize and characterize the nanocomposite of ZnO-Zeolite photocatalyst on the degradation of Cd, Cu, Fe, and Pb heavy metals. The ZnO-Zeolite nanocomposites were characterized by using SEM-EDX, XRD, and BET methods. The degradation caused by exposure to ultraviolet (UV) light occurs within the time of between 60 to 120 minutes, with a pH range of 6–8. The removal of heavy metals proceeds within a time frame of one hour and two hours, resulting in an optimal percentage removal of metals that approaches 100%. The composite showed a surface area of 19.436 m2/g, a pore size of 17.227 Å, and a total pore volume of 0.112 cm3/g. The heavy metals Cu, Fe, and Pb exhibited the highest rates of degradation, reaching their maximum percentages after 60 minutes when exposed to ultraviolet radiation under ideal conditions at varying pH levels (pH 6–8). More precisely, the degradation percentage of Cu metal was 95.4% at pH 7, Fe metal achieved 96.1% at pH 6, while Pb metal obtained 95.5% at pH 8. The Cd metal removal percentage was found to be 98.9% under the conditions of a pH of 8 and an irradiation time of 120 minutes, indicating high effectiveness.

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Laboratory Wastewater Treatment by Using Combination Methods of AOPs and Chemical-Physical Pretreatments

Agustina Tuty Emilia, Arita Susila, Melwita Elda, Bahrin David, Marcelina Revalda, Irdiansyah Hendryal, Karimah Tri

Ecological Engineering & Environmental Technology

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2024

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Vol. 25, iss. 1

216--226

EN

Experimental activities carried out in laboratories usually produce complex wastewater. Due to practicum and research activities in educational laboratories, the wastewater generating from these laboratories contains organic and inorganic compounds which are dangerous for the environment if disposed of without prior treatment. Apart from high chemical oxygen demand (COD) and biological oxygen demand (BOD) values, laboratory wastewater also often contains heavy metals such as zinc (Zn), copper (Cu), chromium (Cr), lead (Pb), and iron (Fe) which are included in the hazardous waste category and can pollute the ground water. Therefore, this wastewater must be treated properly. The objective of this study is to reduce the pollutant load contained in laboratory wastewater by using combination methods of advanced oxidation processes (AOPs), and chemical-physical treatment namely coagulation and adsorption processes. The photo-Fenton process was selected as one of AOPs applied in this treatment. The effect of molar ratio variation and irradiation time in the Photo-Fenton process on the pollution load in the form of pH, COD, BOD, TSS, and heavy metals of Zn, Cu, Cr, Pb, and Fe was studied in this research. The results of the analysis of untreated laboratory wastewater samples showed that laboratory wastewater did not meet the wastewater quality standards regulated by the government of Republic of Indonesia. In this study, laboratory wastewater was treated using the pretreatment method of coagulation with alum and adsorption with activated carbon. The best results in this study were obtained in the final adsorption results after treatment with the photo-Fenton method using a molar ratio of 1: 300 for 60 minutes in which several parameters such as pH, Zn, Cu, Pb, and Fe had met environmental quality standards with the value of each parameter of 7; 0.01 mg/L; 2.9 mg/L; 0.03 mg/L; and 3.15 mg/L respectively. Meanwhile, the percentage reduction of COD, BOD, and TSS parameters was 87.49%, 87.02%, and 72.45% respectively.

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Preparation and Characterization of ZnO-Zeolite Nanocomposite for Photocatalytic Degradation by Ultraviolet Light

Gayatri Rianyza, Agustina Tuty Emilia, Bahrin David, Moeksin Rosdiana, Gustini Gustini

Journal of Ecological Engineering

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2021

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Vol. 22, nr 2

178--186

EN

The increasing growth of the textile industry does not only provide benefits in the economic sector but also has the potential to damage the environment, because it generates the dye wastewater which is hard to eliminate. Procion red is one of the synthetic textile dyes that is toxic to the aquatic environment and it needs to be processed properly. The photocatalytic method of processing dye wastewater is the most effective, because it can remove the harmful pollutants in the dye wastewater. This study aimed to prepare and characterize the ZnO-Zeolite nanocomposites for photocatalytic applications tested with a 50 mg/L procion red dye sample. The nanocomposites consisted of the ZnO semiconductors and synthetic zeolite adsorbents prepared by using the sol-gel method. The dye degradation test was carried out under the irradiation conditions with ultraviolet (UV) lamp. Apart from the ZnO-Zeolite nanocomposite, testing was also carried out with the synthetic zeolite and ZnO. The results of SEM-EDX and XRD characterization proved that the nanocomposite forming components were ZnO and zeolite and could be seen from the resulting peaks. BET showed that the surface area value of the ZnO-Zeolite nanocomposite increased to 95.98 m2/g, the pore size of the ZnO-Zeolite nanocomposite was 4.42 nm, and the total pore volume was 0.08 cm3/g. The obtained average crystalline size of ZnO-Zeolite nanocomposite was 32.87 nm. The percentage of dye degradation using the ZnO-Zeolite nanocomposite for 120 minutes has reached 90.42%.