Ramesh Gade

Bio: Ramesh Gade is an academic researcher from Osmania University. The author has contributed to research in topics: Photodegradation & Photocatalysis. The author has an hindex of 2, co-authored 6 publications receiving 17 citations.

Photodegradation of organic dyes and industrial wastewater in the presence of layer-type perovskite materials under visible light irradiation

Abstract: Layer-type perovskite materials based on AIAIITi2O6 (AI = Na or Ag or Cu and AII = La) system for the degradation of several organic dyes and industrial wastewater under visible-light irradiation are reported. The known perovskite material NaLaTi2O6 (NLTO) was prepared by a new sol-gel process. Ion-exchange of Na+ ions in NLTO with Ag+ or Cu2+ ion led to new perovskite AgLaTi2O6 (ALTO) and Cu0.5LaTi2O6 (CLTO) respectively. All the new materials were thoroughly characterized by using PXRD, FESEM, HRTEM, UV–vis DRS, IR, XPS and Solid State Photo-luminescence techniques. The new series of materials were utilized for the degradation of Congo Red dye, 4-chlorophenol and 4,4′-bis(2-sulfostyryl)biphenyl as reference pollutants, as well as industrial wastewater. The mineralization process of Congo Red was evaluated through mass spectrometry, which showed that after 60 min of irradiation, the dye degraded with all fragments disappeared. Degradation and mineralization of industrial wastewater was studied by using a newly designed photoreactor via a two-stage process. Mechanistic studies for the fast degradation of Congo Red and industrial wastewater were carried out in the presence of various scavengers. Finally, the photomineralized wastewater was evaluated by chemical oxygen demand (COD) test and the obtained value is close to the standard value. Highest efficiency of degradation was found for ALTO as the photocatalyst, followed by CLTO and then NLTO.

A new Zn(II) complex-composite material: piezo-enhanced photomineralization of organic pollutants and wastewater from the lubricant industry

Abstract: In the current work, a ZnO–[Zn(CPAMN)] complex-composite material was used as a piezo-photocatalyst for the mineralization of organic dye pollutants and industrial wastewater. The ZnO–[Zn(CPAMN)] complex-composite material showed higher piezo-photocatalytic activity than a simple complex or ZnO. In contrast, the lower bandgap (2.22 eV) makes it easy for the complex-composite to excite photo-generated species under visible light. Instead, the piezoelectric field initiated from the twisting distortion of [ZnO–Zn(CPAMN)] efficiently enhanced the charge-carrier separation and repositioning. Ultrasonic vibration and visible light radiation applied simultaneously to the complex-composite catalyst mineralized 98% of methyl red (MR) and rhodamine B (RhB) dye solutions during the piezo-photocatalytic process within 60 and 80 min, respectively. The reaction MR constant k of the piezo-photocatalysis process was 50 and 20 times higher than those of sole piezocatalysis and photocatalysis, respectively. The pollutants in industrial wastewater samples were effectively mineralized by over 95% compared to the use of simple piezocatalysis and photocatalysis. Compared to precursor materials such as [Zn(CPAMN)] and ZnO, the significant catalytic activity of the ZnO–[Zn(CPAMN)] complex-composite arose because of heterojunction superiority due to the low rate of recombination of active species and the high surface area.

Effective photodegradation of organic pollutantsin the presence of mono and bi-metallic complexes under visible-light irradiation

Abstract: The synthesis of new mono and bi-metallic complexes such as Zn (II) and Ag-Zn (II) complexes with organic functional group-based ligand (OFL) presented in the current work along with the exploration of their applicability in the photocatalytic degradation of organic dyes under visible-light irradiation. The Zn (II) complex obtained from organic functional group-based ligands, complexed with the donor atoms such as S and N under solvothermal conditions and Ag-Zn (II) complex formed through Ag ions complexed with pyridine ring nitrogen atom. These Zn(II)-complexes were systematically analyzed using the physicochemical studies and other spectroscopic techniques. From these facts, it is clarified that the complexes show square planar geometry with organic functional group-based ligands coordination via mercapto and azomethine groups. The reported complexes were used for the photodegradation of standard organic dye pollutants used in various textile and food processing industries. The complex [Ag-Zn(DCMPPT)(H2O)(OAc)] shows higher photocatalytic activity than [Zn(DCMPPT)(H2O)] because of the high surface area, low bandgap energy and further visible-light available for the initiation of ●OH radicals. To identify the active species in the photocatalytic process, the mechanism process also reported for the fast photodegradation of organic dye pollutants in the existence of some radical quenchers.

Synthesis of new Zn (II) complexes for photo decomposition of organic dye pollutants, industrial wastewater and photo-oxidation of methyl arenes under visible-light

Abstract: Synthesis of new Schiff’s base Zn-complexes for photo-oxidation of methyl arenes and xylenes are reported under visible light irradiation conditions. All the synthesized new ligands and Zn-complexes are thoroughly characterized with various spectral analyses and confirmed as 1:1 ratio of Zn and ligand with distorted octahedral structure. The bandgap energies of the ligands are higher than its Zn-complexes. These synthesized new Zn(II) complexes are used for the photo-fragmentation of organic dye pollutants, photodegradation of food industrial wastewater and oxidation of methyl arenes which are converted into its respective aldehydes with moderate yields under visible light irradiation. The photooxidation reaction dependency on the intensity of the visible light was also studied. With the increase in the dosage of photocatalyst, the methyl groups are oxidized to get aldehydes and mono acid products, which are also identified from LC-MS data. Finally, [Zn(PPMHT)Cl] is with better efficiency than [Zn(PTHMT)Cl] and [Zn(MIMHPT)Cl] for oxidation of methyl arenes is reported under visible-light-driven conditions.

P. putida as biosorbent for the remediation of cobalt and phenol from industrial waste wastewaters

Abstract: The current work focused on the feasibility of treating industrial wastewater containing phenol and cobalt (Co) by adsorption, biosorption, and bioadsorption to determine the effectiveness of each technology. To study the effect of bioadsorption on the removal of phenol and Co, initial studies on biological degradation and adsorption of bacteria and activatedcarbon (AC) had been conducted separately. Results showed that the Langmuir model was the best fitted model for the experimental data over the whole range tested for both the phenol and Co adsorption indicating a monolayer behavior of the consumption process. Moreover, biodegradation results of phenol and Co by P. putida showed a noticeable uptake of phenol to certain concentrations up to 1100 ppm as maximum phenol concentration that P. putida could degrade in which increasing the concentration showed no degradation. Additionally, the optimum phenol concentration by which the degradation was higher and faster was found to be at 700 ppm. In the case of Co, the conducted experiment showed an increase in the uptake of Co with an increase in the initial concentrations up to 10 ppm of Co, and then there was no Co uptake. The bioadsorption experiment which aimed to test the biodegradability of phenol by AC with P. putida and compare it with the degradation of phenol by each factor alone indicated that the uptake of phenol was higher in P. putida and AC + P. putida than using AC alone. Thus, the obtained results clearly showed the effectiveness of using P. putida for the removal of phenol and cobalt from the contaminated effluents.

Perovskite Oxide–Based Materials for Photocatalytic and Photoelectrocatalytic Treatment of Water

Abstract: Meeting the global challenge of water availability necessitates diversification from traditional water treatment methods to other complementary methods, such as photocatalysis and photoelectrocatalysis (PEC), for a more robust solution. Materials play very important roles in the development of these newer methods. Thus, the quest and applications of a myriad of materials are ongoing areas of water research. Perovskite and perovskite-related materials, which have been largely explored in the energy sectors, are potential materials in water treatment technologies. In this review, attention is paid to the recent progress in the application of perovskite materials in photocatalytic and photoelectrocatalytic degradation of organic pollutants in water. Water treatment applications of lanthanum, ferrite, titanate, and tantalum (and others)-based perovskites are discussed. The chemical nature and different synthetic routes of perovskites or perovskite composites are presented as fundamental to applications.

Photoelectrochemical Degradation of Organic Pollutants on a La3+ Doped BiFeO3 Perovskite

Abstract: Towards nonconventional wastewater treatment methods for the degradation of organic pollutants in wastewater, a perovskite-based photoelectrochemical system was developed. Bismuth ferrite doped with lanthanum (La-BiFeO3, La-BFO) perovskite was synthesised through a hydrothermal method with low calcination temperature for the photoelectrochemical degradation of orange II dye and other cocktails of dyes. Photoanodes were prepared by the deposition of the perovskites on a fluorine-doped tin oxide (FTO) substrate. The photoanodes were characterised using XRD, FESEM, FTIR and UV-vis diffuse reflectance. The photoelectrochemical properties of the synthesised photoanodes were investigated with chronoamperometry and electrochemical impedance spectroscopy (including Mott–Schottky analysis). The results show that all La3+-doped BFO photoanodes exhibited a higher absorption edge in the visible light region than the undoped BFO. The photocurrent response of 10% La-BFO (the best performing electrode) exhibited a three times higher current response than the pure BFO. In addition, the electrode exhibited a good degradation efficiency of 84.2% within 120 min with applied bias potential of 2 V at a pH of 7. EIS studies showed a significant enhancement of the interfacial electron transfer of the charge carriers. The enhancements in electrode performances were attributed to the synergistic effect of the applied bias potential and the introduction of La3+ into the BFO matrix. This study therefore shows that the photoelectrocatalytic performance of BFO for water treatment can be improved by the introduction of perovskites-doping ions such as La3+.

Spent Bleaching Earth Supported CeFeO3 Perovskite for Visible Light Photocatalytic Oxidation of Methylene Blue

Abstract: Dyes substances from the textile industry wastewater are internationally classified as poisonous substances, and they cause a severe threat to humans being and other living things, even at low concentrations. Therefore, this waste has to be treated before discharge to the environment. One of the most effective processes for degrading dyes is photocatalytic oxidation. Two different pretreatments of Spent bleaching earth (SBE) from palm oil refinery plant were applied to produce catalyst supports. The SBEe support was prepared by extraction using n-hexane, SBEc by calcination at 500 oC, and then used as a support for CeFeO3/SBEe and CeFeO3/SBEc perovskite catalyst. Both catalysts were tested for the degradation of methylene blue (MB) using photocatalytic oxidation. The properties of catalysts were characterized using some characterization methods, such as thermogravimetric-differential thermal analysis (TG-DTA), X-ray diffraction (XRD), scanning electron microscope (SEM) equipped with Dispersive Energy X-ray Spectroscopy (EDS), specific surface area (BET) and pore size analysis. CeFeO3/SBEe catalyst was found more efficient in photocatalytic oxidation for MB compared with the CeFeO3/SBEc catalyst. CeFeO3/SBEe catalyst could degrade 99.5% of MB during 120 min, at the condition of 25 mg/L MB, 1.0 g/L catalyst, and pH 7. The effect of pH on the performance of the catalyst followed the order of pH 7 > pH 9 > pH 5. Moreover, the CeFeO3/SBEe catalyst demonstrated excellent activity in the degradation of MB, displaying that CeFeO3/SBEe is a favorable catalyst for water purification.