Yazar "Balakrishnan, Deepanraj" seçeneğine göre listele

Listeleniyor 1 - 7 / 7
  • [ X ]
    Öğe
    A comprehensive review on the usability of black phosphorus in energy and wastewater treatment
    (Elsevier Inc., 2024) Kaya, Gul; Eskikaya, Ozan; Kucukosman, Ridvan; Ocakoglu, Kasim; Dizge, Nadir; Balakrishnan, Deepanraj; Singh Chohan, Jasgurpreet
    Increasing population and industrial development brings with it many problems that need to be solved, such as energy production, storage, saving, protection of limited reserves, and environmental pollution. Nanomaterials, which emerged with the introduction of nanotechnology into our lives, play an important role in many areas. The novel two-dimensional nanomaterial black phosphorus (BP) exhibits great potential in photocatalytic applications, energy technologies, and purification with properties such as broad light absorption spectrum, tunable direct band gap, and exceptionally high charge carrier mobility. This review gives a outline of the manufacturing techniques, structural, chemical, electrical and thermal properties of BP. Then, the success of BP derivatives with different dimensions and morphologies in environmental and energy applications is presented by comparing them with previous studies in these fields. The results show that heterojunction structures produced by combining BP with MoS2 and MOFs improve the electrochemical properties of BP, while carbonization processes increase its efficiency in battery and supercapacitor applications. Finally, in this review, a summary of BP's potential future uses, awareness of easy production methods, and its activities in environmental and energy applications are discussed in a broad context. © 2024
  • [ X ]
    Öğe
    Caustic recovery from caustic-containing polyethylene terephthalate (PET) washing wastewater generated during the recycling of plastic bottles
    (Nature Portfolio, 2025) Alterkaoui, Aya; Eskikaya, Ozan; Keskinler, Bulent; Dizge, Nadir; Balakrishnan, Deepanraj; Hiremath, Pavan; Naik, Nithesh
    To prevent water scarcity, wastewater must be discharged to the surface or groundwater after being treated. Another method is to reuse wastewater in some areas after treatment and evaluate it as much as possible. In this study, it is aimed to recover and reuse the caustic (sodium hydroxide, NaOH) used in the recycling of plastic bottles from polyethylene terephthalate (PET) washing wastewater. Chemical substances used in the industry will be significantly reduced with chemical recovery from wastewater. Ultrafiltration (UP150) and nanofiltration (NP010 and NP030) membranes were used for this purpose in our study. Before using nanofiltration membranes, pre-treatment was performed with coagulation-flocculation process to reduce the pollutant accumulation on the membranes. Different coagulants and flocculants were used to find suitable coagulants and flocculants in pre-treatment. The pre-treated wastewater using aluminum oxide, which supplied the highest chemical oxygen demand (COD) removal (76.0%), was used in a dead-end filtration system to be filtered through NP010 and NP030 membranes at different pressures (10-30 bar). In the same filtration system, raw wastewater was filtered through a UP150 membrane. Among these treatment scenarios, the best method that could remove pollutants and provide NaOH recovery was selected. After each treatment, pH, conductivity, COD, and NaOH analyses were performed. The maximum NaOH recovery (98.6%) was obtained with the UP150 membrane at 5 bar.
  • [ X ]
    Öğe
    Comparison of Cr(VI) adsorption and photocatalytic reduction efficiency using leonardite powder
    (Pergamon-Elsevier Science Ltd, 2022) Arslan, Hudaverdi; Eskikaya, Ozan; Bilici, Zeynep; Dizge, Nadir; Balakrishnan, Deepanraj
    It is very important to treat Cr(VI) from the aquatic environment due to its toxic and harmful effects. Conventional treatment methodology involving biological pathways is generally ineffective for wastewater containing Cr(VI). Therefore, it is necessary to develop environmentally friendly and economical methods to remove Cr(VI) from the aquatic environment. In this study, leonardite, which is a natural mineral that has no harmful effects on the environment, was used for Cr(VI) removal. Leonardite was used in both adsorption and photocatalytic treatment systems by only pulverizing without any chemical treatment. Characterizations of leonardite were obtained using X-ray fluorescence (XRF), fouirer transform infrared spektrofotometre (FTIR), scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX) analyses methods. The effects of solution pH (2-10), particle size (45-300 mu m), adsorbent dose (0.25-3 g/L), and initial concentration (10-30 mg/L) on Cr(VI) removal efficiency were investigated in both adsorption and photocatalytic experiments. In the adsorption process, a complete removal efficiency (100%) was obtained for 3 g/L of adsorbent dose with an initial Cr(VI) concentration of 10 mg/L at pH 2 for 2 h. In the photocatalytic process, 100% removal efficiency of Cr(VI) was obtained when four times less adsorbent dosage was used under the same conditions. In addition, the reuse of leonardite powder was also investigated under optimum experimental conditions. Leonardite powder preserved approximately 70% of its activity in the photocatalytic process while it lost 50% of its activity after 5 reuses in adsorption process.
  • [ X ]
    Öğe
    Enhanced biogas yield in anaerobic digestion of citric acid wastewater by pre-treatment: The effect of calcium hydroxide precipitation and electrocoagulation process
    (Elsevier, 2024) Belibagli, Pinar; Akbay, Habibe Elif Gulsen; Arslan, Salih; Mazmanci, Birgul; Dizge, Nadir; Senthilkumar, Natarajan; Balakrishnan, Deepanraj
    During the production and use of citric acid (CA), which is frequently used in food, chemistry, metallurgy and other related industries, wastewater with high organic load and acidity is generated. Discharge of these wastewaters into the receiving environment without adequate purification causes serious pollution problems. However, treating such wastewater with hybrid processes allows both the formation of valuable by-products and an increase in the degree of purification. In this study, the biogas production potential of citric acid wastewater (CAWW), which was pre-treated by chemical precipitation and electrocoagulation (EC) processes, was investigated. Pre-treatment experiments were designed using Box-Behnken Design (BBD) and chemical oxygen demand (COD) concentrations after hydrated lime (Ca(OH)2) precipitation and EC processes were determined as 4960 mg/L and 5120 mg/L, respectively. The pre-treated CAWW were finally used for the secondary treatment by anaerobic digestion (AD) process. After AD process COD degradation determined as 67% and 98% for Ca (OH)2 precipitation and EC process, respectively. In addition, the biogas production of the pre-treated CAWW increased approximately 2 and 7 times for the Ca(OH)2 precipitation and EC processes, respectively, compared to the untreated. The methane (CH4) content of the produced biogas increased by 18% and 50% for Ca(OH)2 precipitation and EC processes, respectively. According to 48-hour acute toxic test result, daphnia mortality decreased from 50% concentration of CAWW after AD, even 10% concentration is non-toxic to daphnia. In conclusion, the complementarity of Ca(OH)2 precipitation and EC processes with AD promoted both the removal of organics from wastewater and the production of valuable by-products.
  • [ X ]
    Öğe
    Heterogeneous catalyst production from waste cucumber stems and investigation of production potential in biodiesel
    (Elsevier, 2025) Alterkaoui, Aya; Belibagli, Pinar; Arslan, Hudaverdi; Dizge, Nadir; Balakrishnan, Deepanraj
    The use of heterogeneous catalysts obtained from waste in biodiesel production is of great importance in terms of waste management and waste recovery. In this study, heterogeneous catalyst was successfully obtained from waste cucumber stems (WCS) and its potential for biodiesel production via transesterification was investigated. The heterogeneous catalyst contains Ca, K, Mg, Si elements that play a role in biodiesel production. Biodiesel production potential was designed by selecting different temperature, time, methanol/oil molar ratio, and catalyst amount using response surface methodology (RSM). Waste cooking oil (WCO) was used for biodiesel production. The optimum values of these parameters were found to be 70 degrees C, 120 min, 15 wt% and 20:1, respectively. 93.7 % FAME yield was obtained using the obtained CaO catalyst. The heterogeneous catalyst obtained from WCS showed multiple reuse capacity up to 5 cycles. All these results showed that the heterogeneous catalyst obtained from WCS has strong biodiesel production activity and this approach has great potential in biodiesel production with its economic, sustainability and environmental benefits.
  • [ X ]
    Öğe
    Optimization of chromium (VI) reduction in aqueous solution using magnetic Fe3O4 sludge resulting from electrocoagulation process
    (Public Library Science, 2024) Belibagli, Pinar; Isik, Zelal; Dizge, Nadir; Balakrishnan, Deepanraj; Afzal, Abdul Rahman; Akram, Muhammad
    The reuse of electro-coagulated sludge as an adsorbent for Cr(VI) ion reduction was investigated in this study. Electro-coagulated sludge was obtained during the removal of citric acid wastewater by the electrocoagulation process. The following parameters were optimized for Cr(VI) reduction: pH (5-7), initial Cr(VI) concentration (10-50 mg/L), contact time (10-45 min), and adsorbent dosage (0.5-1.5 g/L). Cr(VI) reduction optimization reduction experimental sets were designed using response surface design. Cr(VI) reduction optimization results 97.0% removal efficiency and 15.1 mg/g adsorption capacity were obtained at pH 5.0, 1.5 g/L electro-coagulated Fe3O4 sludge, 10 mg/L initial Cr(VI) concentration and 45 min reaction time. According to the isotherm results, the experimental data are compatible with the Freundlich isotherm model, and since it is defined by the pseudo-second order model emphasizes that the driving forces of the Cr(VI) reduction process are rapid transfer of Cr(VI) to the adsorbent surface. The reusability of the adsorbent was investigated and Cr(VI) reduction was achieved at a high rate even in the 5th cycle. All these results clearly show that electro-coagulated Fe3O4 sludge is an effective, inexpensive adsorbent for Cr(VI) removal from wastewater.
  • [ X ]
    Öğe
    Photocatalytic activity of calcined chicken eggshells for Safranin and Reactive Red 180 decolorization
    (Pergamon-Elsevier Science Ltd, 2022) Eskikaya, Ozan; Gun, Melis; Bouchareb, Raouf; Bilici, Zeynep; Dizge, Nadir; Ramaraj, Rameshprabu; Balakrishnan, Deepanraj
    One of the most important problems affecting the environment today is the inability to adequately treat wastewater containing dyes. Among of the many treatment processes used in the treatment of dye-containing wastewater, photocatalytic based wastewater treatment processes attract the attention of scientists as a new, economically feasible, and promising approach which has been in practice for a few decades. However, in order to use these processes in wider areas, cheap and effective catalysts are still being developed today. In this study, the photocatalytic activity of eggshell-CaO produced from waste chicken eggshells was investigated for decolorization of Safranin (Basic Red 2) and Reactive Red 180 (RR180) dyes. First, sintering process was applied to the waste chicken eggshells at different temperatures (300, 600, 900 degrees C) in order to observe CaO formation from the eggshells. Second, the parameters such as photocatalyst amount, pH, concentration of dyes, and reaction time were optimized on dye removal efficiency in photocatalytic experiments. The optimum conditions were performed under visible light and found to be 1 g/L of catalyst amount (sintered at 900 degrees C), original solution pH (6.80 for Safranin and 6.60 for RR180), and 5 mg/L of dye concentration. The photocatalytic removal efficiencies of Safranin and RR180 dyes were 100% and 97.90%, respectively, under the determined optimum experimental conditions. The adsorption efficiency of the dyes that could be realized during the photocatalytic experiment was measured as 20.99% and 9.99% for Safranin and RR180 dyes, respectively.