Synthesis, characterization, and photocatalytic performance evaluation of manganese tungstate for methyl red dye degradation

Abstract

The increasing prevalence of synthetic dyes in industrial wastewater presents significant environmental challenges because of the toxicity and lack of effectiveness of conventional treatment methods. Methyl red, a widely used azo dye, is particularly problematic due to its high chemical stability. In this study, manganese tungstate (MnWO₄) was synthesized using a coprecipitation method and evaluated for its photocatalytic activity in methyl red degradation through UV-C exposure. The synthesized MnWO₄ was characterized using several techniques, including Fourier transform infrared spectroscopy (FTIR), ultraviolet-diffuse reflectance spectroscopy (UV-DRS), and scanning electron microscopy (SEM). SEM analysis revealed the formation of needle-like, nanometer-sized MnWO₄ particles with high aspect ratios, which are expected to enhance photocatalytic efficiency. XRD confirmed the development of a highly crystalline pure MnWO₄ phase, and FTIR spectra showed characteristic peaks corresponding to Mn-O and W-O bonds. The UV-DRS results revealed that the material possesses a direct band gap of 3.18 eV, suitable for UV-C light absorption. Photocatalytic experiments demonstrated that MnWO₄ effectively degraded methyl red, with the removal efficiency reaching nearly 60% after 180 minutes of irradiation. These findings suggest that MnWO₄ is a promising photocatalyst for environmental remediation, offering a simple, cost-effective solution for dye degradation in wastewater.

Keywords

• Manganese tungstate (MnWO₄)
• Photocatalysis
• Methyl red degradation
• Wastewater treatment
• Dye degradation
• Environmental remediation

Mangan tungstatın sentezi, karakterizasyonu ve metil kırmızı boya giderimi için fotokatalitik performans değerlendirmesi

Öz

Sentezlenen sentetik boyaların sanayi atıksularındaki artan yaygınlığı, toksisiteleri ve geleneksel arıtma yöntemlerine karşı dirençleri nedeniyle önemli çevresel zorluklar yaratmaktadır. Yaygın olarak kullanılan bir azo boyası olan metil kırmızı, yüksek kimyasal kararlılığı nedeniyle özellikle sorun teşkil eder. Bu çalışmada, manganez tungstat (MnWO₄), ko-precipitasyon yöntemi kullanılarak sentezlenmiş ve UV-C ışınımı altında metil kırmızının fotokatalitik bozunumu için değerlendirilmiştir. Sentezlenen MnWO₄, X-ışını kırınımı (XRD), Fourier dönüşüm infrared spektroskopisi (FTIR), Ultraviyole-difüz reflektans spektroskopisi (UV-DRS) ve Taramalı elektron mikroskobu (SEM) gibi çeşitli tekniklerle karakterize edilmiştir. SEM analizi, yüksek açısal oranlara sahip iğne benzeri, nanometre boyutlarında MnWO₄ parçacıklarının oluşumunu ortaya koymuştur, bu da fotokatalitik verimliliği artırması beklenen bir özelliktir. XRD, yüksek kristal yapıda saf bir MnWO₄ fazının oluşumunu doğrulamış ve FTIR spektrumları, Mn-O ve W-O bağlarına karşılık gelen karakteristik pikleri göstermiştir. UV-DRS sonuçları, malzemenin UV-C ışığı emme için uygun olan 3.18 eV'lik bir direk bant aralığına sahip olduğunu göstermektedir. Fotokatalitik deneyler, MnWO₄'ün metil kırmızıyı etkin bir şekilde bozduğunu ve 180 dakika sonra bozunma verimliliğinin neredeyse %60'a ulaştığını göstermiştir. Bu bulgular, MnWO₄'ün çevresel iyileştirme için umut verici bir fotokatalizör olduğunu ve atıksulardaki boya bozulması için basit ve maliyet etkin bir çözüm sunduğunu göstermektedir.

Anahtar Kelimeler

• Mangan tungstat (MnWO₄)
• fotokataliz
• metil kırmızı bozunumu
• atıksu arıtımı
• boya bozunumu
• çevresel iyileştirme

Kaynakça

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