Optimum Conditions For Removal Research Articles

Phycoremediation of Phenolphytalein, Indigo Carmine, Methyl Orange and Eriochrome Black T By Using Chlamydomonas and Chlorella sp. (Chlorophyta)

This work aimed to evaluate the decolorization of phenolphthalein (PP), indigo carmine (IC), methyl orange (MO) and eriochrome black T (EBT) by using Chlorella and Chlamydomonas as a biosorbent. This experiment used the batch adsorption method to study the adsorption effect of pH, biomass dosage, contact time, initial dye concentration and temperature on the dyes. The adsorption of the dyes onto the cells were fitted with the Langmuir and Freundlich isotherms. The results showed that the optimum conditions for PP removal (99%) was obtained at pH 4, contact time of 120min, 35°C, algal dosage of 0.5 mg/mL and dye concentration of 100 mg/L on to the cells. The sample prepared at 25°C, 120 min, 1 mg/mL algal dosage, 25 mg/L dye concentration and at pH 4 had the best adsorption effect on IC on to the both of cells (99-98%). In addition, the optimum conditions for MO and EBT removal (99-97%) was obtained at pH 2-4, contact time of 30 min, 25°C, algal dosage of 0.5mg/mL and dye concentration of 100mg/L. The results of this study reveal that the algae cells can be utilized as an efficient and eco-friendly biosorbent for the removal of the indicator dyes from aqueous solution.

Synthesis and application of dual-functional sorbent SBA-15-Fe3O4-PDA-ODA for removing both water soluble and insoluble pollutants

In this study, inorganic-organic hybrid sorbent SBA-15-Fe3O4-PDA-ODA with functional groups having affinity for both water-soluble and insoluble pollutants was synthesized for treatment of wastewater where Malachite Green (MG) dye and motor oil coexist. In order to enhance the specific interactions between the sorbent and dye via functional groups of polydopamine (PDA), Fe3O4 nanoparticles were encapsulated with SBA-15 and surface functionalization with PDA was accomplished and then the surface of Fe3O4-SBA-15-PDA was modified with octadecylamine (ODA) to remove the oil present in the same environment with dye. While the SBA-15-Fe3O4-PDA-ODA directed to the aqueous phase by magnet provided MG removal thanks to the hydrophilic groups of PDA, it provided motor oil removal thanks to hydrophobicity of ODA when directed to the oil phase. 99.20 % dye removal and 9.24 g/g oil adsorption capacity were achieved from the environment where oil and dye were present together. Besides, the adsorption of MG on Fe3O4-SBA-15-PDA was searched at various pH, dye concentration, adsorbent dosage, and temperature in order to propose optimum experimental conditions for removal of dye and maximum adsorption capacity was determined as 95.83 mg g−1 at optimum conditions (10 mg adsorbent, 10 mg L−1 MG concentration, pH 9). Interaction mechanism between dye and Fe3O4-SBA-15-PDA was explained by studying the adsorption behavior of sorbent derived from the isotherm and kinetic results. The sorbents were characterized by FT-IR, XRD, SEM, N2-adsorption/desorption, water-contact-angle, and VSM measurements. SBA-15-Fe3O4-PDA-ODA sorbent was tested for three successive adsorption cycles for both dye and oil and eventuated insignificant loss in activity when they were recycled. Easy and low-cost fabrication protocol, controllable removal ability of dye and oil will facilitate its versatility in environmental cleanup process for water soluble and insoluble pollutants.

Process optimization of Cd2+ removal with Tetradesmus Obliquus-immobilized Algal Beads

In this study, calcium alginate-immobilized microalgae beads were utilized for treating Cd2+-containing wastewater by optimizing the algal species, the preparation conditions of immobilized beads, and the Cd2+ treatment conditions to enhance treatment efficiency. The results revealed that under optimal preparation conditions with a CaCl2 concentration of 3 % and a sodium alginate concentration of 2 %, the removal rate of Cd2+ reached 94.99 % after 3 h of adsorption when 4 g of immobilized Tetradesmus obliquus algal beads were added to a 20 mg/L Cd2+ solution. Additionally, under optimal removal conditions at pH=6, with immobilized Tetradesmus obliquus algal beads as the adsorbent and a dosage of 6 g of immobilized algal beads added to a solution with an initial Cd2+ concentration of 15 mg/L, the Cd2+ removal rate reached 99.85 % after 4 h of adsorption, surpassing that of suspended microalgae and blank algal beads. The adsorption process followed the pseudo-second-order kinetic model and the Langmuir adsorption isotherm model. FTIR analysis indicated that functional groups such as O-H, CO, C-O, C-N, among others, might play a role in the adsorption process. After five adsorption-desorption cycles, the adsorption capacity decreased by only 10 %. This study demonstrated that immobilized Tetradesmus obliquus algal beads is an efficient and renewable and recyclable adsorbent.

CoFe2O4/PANI/MWCNTs ternary hybrid composites. Synthesis, characterization, the effect of MWCNTs ratio and dye removal capability.

We have synthesized cobalt ferrite (CoFe2O4) using the sucrose auto-combustion method and subsequently employed the in situ polymerization technique to fabricate ternary composites comprising CoFe2O4, polyaniline (PANI), and multi-walled carbon nanotubes (MWCNTs). In this novel investigation, we explored the influence of varying MWCNTs ratios on these composites' structural, magnetic, thermal, and electrical properties. The crystal structures of the synthesized composites were analyzed using X-ray diffraction (XRD), while Fourier transform infrared (FT-IR) spectroscopy revealed changes in bonding patterns, including the disappearance of ferrite bonds and the emergence of new ones. Transmission electron microscopy (TEM) images illustrated a complete coating of PANI on both MWCNTs and CoFe2O4 particles, resulting in a substantial reduction in magnetization compared to pure CoFe2O4 ferrite due to PANI's nonmagnetic nature. Vibrating sample magnetometer (VSM) measurements confirmed this reduction, indicating a decrease to 7.3 emu.g-1. Thermal analysis demonstrated an enhancement in thermal stability with increasing MWCNTs content, as evidenced by an increase in the temperature equivalent for half decomposition (T50) from 486 to 522°C for composites with 40% MWCNTs. Moreover, the electrical conductivity showed a corresponding rise with MWCNTs content, increasing from 3.1 × 10-3 Ω-1.cm-1 to 2.2 × 10-2 Ω-1.cm-1, possibly indicating charge transfer from PANI to MWCNTs. To assess practical applications, we investigated the ability of the composite with 40% MWCNTs to remove phenol red (PR) dye from aqueous solutions. Through a systematic study of adsorption parameters and kinetics, we determined optimal conditions for effective dye removal and elucidated the underlying adsorption mechanism. Our results demonstrated the composite's efficiency in dye removal, with a 6.4mg·g-1 capacity for PR dye, highlighting its potential for environmental remediation efforts.

Effective Degradation of Metronidazole through Electrochemical Activation of Peroxymonosulfate: Mechanistic Insights and Implications

The investigation into the degradation of metronidazole (MNZ), a frequently employed antibiotic, through the electrochemical activation of peroxymonosulfate (PMS) utilizing either boron-doped diamond (BDD) or dimensional stable anode (DSA) as the anode, was conducted in a systematic manner. The enhancement of MNZ removal was observed with increasing current density, PMS dosage, and initial pH. Response surface methodology (RSM), based on a Box–Benken design, was utilized to evaluate the efficiency of MNZ elimination concerning current density (ranging from 11.1 to 33.3 mA/cm2), initial pH (ranging from 3 to 9), PMS dosage (ranging from 1 to 5 mmol·L−1), and reaction time (ranging from 25 to 45 min). The optimal operational conditions for MNZ removal were determined as follows: a current density of 13.3 mA/cm2, a pH of 3.7, a PMS dosage of 2.4 mmol·L−1, and a reaction time of 40 min. Electron paramagnetic resonance (EPR), quenching experiments, and chemical probe experiments confirmed the involvement of •OH, SO4•− and 1O2 radicals as the primary reactive species in MNZ degradation. The presence of HCO3− and H2PO4− hindered MNZ removal, whereas the presence of Cl− accelerated it. The degradation pathways of MNZ were elucidated by identifying intermediates and assessing their toxicity. Additionally, the removal efficiencies of other organic pollutants, such as sulfamethoxazole (SMX), carbamazepine (CBZ), and nitrobenzene (NB), were compared. This study contributes to a comprehensive understanding of MNZ degradation efficiency, mechanisms, and pathways through electrochemical activation of PMS employing BDD or DSA anodes, thereby offering valuable insights for the selection of wastewater treatment systems.

Application of response surface methodology for optimization of removal sunset yellow from aqueous by Granular Ferric Hydroxide (GFH)

Color is the first pollutant that is detected in wastewater and can be discharged into the wastewater through various industries. Sunset yellow is an azo dye that is used in the food, health and pharmaceutical industries. Due to its low price and good quality, this color is used in industries more than natural colorants. The aim of this study was to investigate the effect of granular ferric hydroxide (GFH) on the removal of sunset yellow color from aqueous solution using the response surface methodology (RSM). In this study, GFH was employed to remove sunset yellow dye from the aqueous solution. Due to saving time, cost and getting to the optimum conditions, the effect of important factors on adsorption was optimized by the RSM. The morphology of the adsorbent was determined by scanning electron microscopy. The results revealed that optimum conditions for sunset yellow removal by GFH with design experiment were dye concentration= 24 mg/L, GFH dose= 2.4 g/L, reaction time= 25 min. In addition, based on the results, the best-fitted model for this study was the quadratic model (R2 =0.966, R2adj=0.79 and R2pred=0.936). According to the obtained results, GFH was successful in sunset yellow removal. Therefore, it is suggested to use this process to remove sunset yellow from aqueous solutions.

Iron terephthalate metal-organic framework (MOF‑235) modified with zinc as an efficient adsorbent for removal of tetracycline from aqueous solution

The study focused on synthesizing and modifying the MOF235-Zn composite to enhance its catalytic properties for removing tetracycline from water systems. Incorporating zinc into the MOF235 structure significantly improved its efficiency in tetracycline removal. Characterization methods such as SEM, mapping, EDS, and FTIR confirmed the successful synthesis and modification of the MOF235-Zn composite. The addition of zinc reduced the time needed for tetracycline removal and minimized the required amount of MOF235-Zn, even at room temperature. The study also investigated the impact of operational parameters on tetracycline adsorption and identified optimal conditions for tetracycline removal. Overall, the findings highlight the potential of the MOF235-Zn composite to effectively remove tetracycline, particularly under optimized operational conditions.

Heavy metals removal from industrial wastewater using date seeds powder and aluminum chloride-based hybrid natural/chemical coagulation

High levels of heavy metals in industrial wastewater pose a significant environmental concern due to their toxicity to living organisms and ecosystems. Traditional techniques that use chemical coagulants to eliminate heavy metals from industrial wastewater have proven effective. However, the use of chemical coagulants produces sludge that is highly toxic and requires careful management. On the other hand, natural coagulants offer a cost-effective and sustainable alternative that is safer to handle, locally available, and potentially useful for resource recovery. These benefits make natural coagulants a promising substitute for chemical coagulants. This study aimed to investigate the performance of combining Date stone powder (DSP) and aluminum chloride (AlCl3), to remove heavy metals from industrial wastewater efficiently. Through an optimization process of DSP/AlCl3 dosage and pH, the study sought to determine the optimal conditions for heavy metal removal. The main findings indicate that a DSP/AlCl3 dosage of 7:1 (g/g) was the most effective coagulant dosage, resulting in high removal efficiencies for COD (88.56%), color (89.56%), TSS (99.00%), NH3-N (92.50%), Mn (94.10%), Fe (95.47%), Zn (93.57%), Al (88.42%), and Ni (93.3%) at pH 8. Interestingly, the results of pH optimization showed that no pH modification was necessary, as it already achieved high removal efficiencies for COD (84.57%), color (88.94%), TSS (99.00%), NH3-N (92.25%), Mn (92.66%), Fe (90.57%), Zn (95.59%), Al (99.00%), and Ni (93.33%). This study demonstrates that the hybrid DSP/AlCl3 coagulation method can be an effective and sustainable solution for removing heavy metals from industrial wastewater. However, further research is necessary to assess its scalability and potential limitations.

Stability and kinetic insights for ibuprofen removal from aquaculture wastewater using green supported ionic liquid membranes

Pharmaceutical residues in aquaculture effluent have become a growing environmental concern due to their potential ecological impacts. Supported ionic liquid membranes (SILM) offer a promising solution for extracting micropollutants from contaminated sources. SILM was developed using Aliquat 336 in sunflower oil (SFO) as a carrier solution, specifically targeting ibuprofen (IBP) in aquaculture wastewater. Different solid supports are fabricated through the nonsolvent-induced phase separation (NIPS) process and characterized by SEM, EDX, contact angle, FTIR and porosimeter. PVDF support is selected as solid support for immobilization of the carrier solution owing to its properties of having an asymmetrical shape, thickness of 48.8 µm, porosity of 72% and contact angle of 89.0° (feed side) and 85.3° (stripping side). The percentage of carrier loss obtained was only 1.10%. The optimal conditions for IBP removal were obtained at 0.50 M Aliquat 336, with a feed phase pH of 5.5 and stripping phase pH of 8. Further tests on real aquaculture wastewater affirmed the system’s efficacy in removing IBP and maintaining the stability at least the fifth cycle of membrane reusability. This study underscores the viability of proposed SILM system in mitigating IBP from aquaculture sector.

Applying circular economy principles and life cycle assessment: A novel approach using vine shoots waste for cadmium removal from water

This research investigates the potential of utilizing vine shoots, a byproduct of the viticulture industry, as biosorbent for cadmium removal from aqueous solutions. The Spanish wine industry, one of the most influential sectors, produces two to three million tons of vine shoots. By using vine shoots as biosorbent, this study contributes to the circular economy paradigm, transforming waste materials into valuable resources and minimizing environmental impacts associated with waste generation and disposal. The research underscores the significance of vine shoots in biosorption due to its high lignocellulosic content. By experimental analysis, the efficacy of vine shoots in cadmium biosorption is evaluated, considering factors such as environmental impact or energy consumption. This study examines the effect of six key input parameters on cadmium removal efficiency and power consumption, identifying optimal conditions for maximum removal with minimal energy consumption. The findings suggest that vine shoots offer promising biosorption capabilities, promoting sustainability in wastewater treatment and environmental remediation efforts. By employing the response surface method alongside desirability functions, the study determined the optimal variables for two distinct optimization scenarios. Notably, in the second optimization scenario, a cadmium removal rate of 99.23 % was achieved while consuming 25.6 W of power. The input parameters for this achievement should be set as follows: initial cadmium concentration of 100 ppm, pH level of 8, stirring time of 75 min, stirring speed of 100 rpm, temperature of 26 °C, and a dose of vine shoots of 0.1 g.

Congo Red Removal from Polluted Water using NaOH Treated Fallen Leaves of Ficus racemosa

Naoh treated biosorbent Ficus Racemosa Leaf Powder (NaFRLP) was prepared from the fallen leaves of the plant. FT-IR, SEM and BET analysis were done to characterize the biosorbent. The biosorbent was found to be mesoporous with an average pore size 18 nm. Batch adsorption equilibrium studies were conducted for the adsorption of congo red on NaFRLP as a function of adsorbent dosage, agitation speed, dye concentration, temperature and contact time. Batch adsorption studies revealed that with an increase in the time of adsorption, the percentage removal of congo red increases and with an increase in the concentration of dye solution, congo red removal decreases. Initial dye concentration of 100 mgL-1, agitation speed 200 rpm and adsorbent dosage 1gL-1 were the optimum conditions for the effective removal of congo red. The adsorption data well agreed with the Langmuir isotherm as indicated by the higher correlation coefficient (R2=0.962) value. Thermodynamic analysis of the batch adsorption studies indicated that all the processes studied were spontaneous with the congo red adsorption on NaFRLP being endothermic. Intra particle diffusion model was also tested. NaFRLP was found to be an effective adsorbent for the removal of congo red from the polluted water.

Investigating the Efficiency of Photo-Fenton (UV/H2O2/Fe2+) in Removing the Indomethacin Antibiotic From Aqueous Solutions

Water pollution caused by antibiotics is one of the major challenges in the world today. The current research aims to investigate the effect of the Photo-Fenton process in removing indomethacin antibiotics from aqueous solutions. This experiment-based study was conducted on a laboratory scale and discontinuous manner. The influential variables affecting the removal efficiency of indomethacin include initial antibiotic concentration, pH, time, hydrogen peroxide concentration, and iron ion. The study was conducted base on standard methods (APHA, AWWA, CFWP, 2005). The Design Expert software was used to analyze the effect of independent variables on the removal efficiency of indomethacin antibiotics in the Photo-Fenton process (UV/H2O2/Fe2+) using response surface methodology (RSM) and central composite design (CCD). To ensure the repeatability of the results, each experiment was repeated three times and the reported the average. The results showed that the optimal removal conditions for indomethacin antibiotics were pH = 4, H2O2 oxidant concentration = 50 ppm, Fe2+catalyst concentration = 50 ppm, time = 75 minutes, and initial antibiotic concentration = 20 ppm, with a removal efficiency of 91.03% . The variables of initial antibiotic concentration, H2O2 concentration, and pH had the greatest impact on the removal efficiency of indomethacin. The results of this study indicate that under optimal conditions, more than 90% of indomethacin antibiotics can be removed from aqueous solutions using the Photo-Fenton process, which is a significant result for removing this pharmaceutical pollutant from aquatic environments.

Three-dimensional electrochemical Fenton degradation of CIP by doping Ce and Cu in Jacaranda shell base as particle electrodes

Currently, ciprofloxacin (CIP) in water environments has attracted wide attention. In order to degrade CIP by electrocatalysis, it is very important to develop catalysts with high catalytic activity as particle electrodes. In this study, Jacaranda shell was made into biochar (BC) by calcination, Ce and Cu modified BC (Ce-Cu/BC) was prepared by a simple impregnation and calcination method as a particle electrode in a three-dimensional electro-Fenton (3D/EF) system to degrade CIP. Characterization of the Ce-Cu/BC particle electrodes was conducted using SEM, XRD, and XPS, revealing the porous structure of the calcined jacaranda shell base, confirming successful loading of Ce and Cu. Optimal operating conditions for CIP removal were determined to be 4 g/100 mL particle electrodes dosage, initial pH of 5, 8 V voltage, and 2 mM Fe2+ concentration, resulting in a maximum CIP removal rate of 84.97% with an energy consumption of 1.32 W•h. Stability tests demonstrated the robustness of Ce-Cu/BC, while comparative tests and radical extinction experiments highlighted the high electrocatalytic activity of the 3D/EF system, primarily attributed to the indirect oxidation of •OH, an active substance generated within the system LC-MS and UV full-band scanning analyses were employed to propose potential CIP degradation pathways.

Batch adsorption of diesel oil in water using saba banana peel biochar immobilized in teabags

Diesel oil contamination is a threat to environment and human health. Many technologies have been developed to address this issue; however, they are costly to be deployed in real-world oil remediation. Adsorption remains to be one of the most economical methods to remove oil from water. Here, we used banana peel biochar (BPBC) immobilized in teabags as an adsorbent for the removal of diesel oil in water. We investigated the adsorption behavior of BPBC under different conditions, examining the influence of adsorbent loading, pH, salinity, and contact time on its efficiency for removing diesel oil in water. Our results show that the sorption capacity of BPBC is significantly affected by the amount of adsorbent used. Lower biochar loadings enhance the sorption capacity due to greater surface area accessibility, while higher loadings lead to decreased efficiency due to pore blockage and reduced surface exposure. Interestingly, the pH of the solution was found to have minimal impact on the sorption process. This is attributed to diesel oil’s hydrophobic and non-polar nature, which leads to its interaction with BPBC being predominantly governed by hydrophobic forces instead of pH-sensitive electrostatic interactions. Salinity emerged as a crucial factor in the adsorption process. An increase in salinity enhances the sorption capacity, likely due to the “salting-out” effect, where higher salt concentrations decrease the solubility of diesel oil, promoting its adsorption onto the biochar surface. Furthermore, the study highlights the importance of contact time, with longer exposure resulting in increased sorption capacity. This trend is explained by the adsorption kinetics, initially characterized by rapid adsorption, followed by a slower, progressive occupation of the biochar’s adsorption sites. The kinetic analysis of the process suggests that the pseudo-second-order model is more suitable, indicating a chemisorption mechanism. The Harkins–Jura isotherm model was identified as the best fit for explaining the isotherm behavior, owing to its capacity to account for the heterogeneous nature of the biochar surface and the formation of multiple adsorbate layers. The optimum conditions for maximum diesel oil removal are as follows: BPBC loading of 0.50 g, a solution pH of 5.00, a salinity concentration of 12,656.57 mg/L, and a contact time of 240 min. Under these conditions, BPBC exhibited an adsorption capacity of 19.04 g/g. In summary, our research establishes BPBC, particularly when contained within teabags, as an efficient and practical adsorbent for diesel oil removal in water. Its effectiveness, superior to other biochar, is mainly due to its porosity and hydrophobic properties. These findings not only enhance our understanding of BPBC’s adsorption capabilities but also underscore its potential for environmental remediation.Graphical

The structure of deposited coke on hydrocracking and reforming catalysts: Coke deactivation and kinetics

AbstractThis comprehensive study investigates the structural deposition of coke, particularly its association with sulphides, in spent hydrocracking and reforming catalysts, leveraging advanced kinetic modelling and characterization techniques. Its objective is to elucidate coke removal kinetics, offering insights into optimizing catalyst regeneration. Utilizing thermogravimetric analysis, spectroscopic methods, and modelling, the research outlines the characteristics and kinetic behaviour of coke during regeneration. The novelty aspect of this study is the use of a reaction‐based model for accurate kinetic analysis and identifying optimal conditions for coke removal. The study recognized both hydrogen‐deficient and hydrogen‐rich amorphous coke, alongside graphitic coke spent catalysts. Thermogravimetric analysis revealed that coke constitutes ~23.8% and 4.6% of the total weight in hydrocracking and reforming catalysts, respectively. The traditional model‐free method for deactivation was found inadequate in predicting coke in the spent reforming catalyst, likely due to the presence of low‐temperature hydrocarbons of soft coke within the catalyst pores. In contrast, a reaction model‐based deactivation approach yielded more consistent evaluations for soft and hard coke of spent catalyst. For the spent hydrocracking catalyst, the estimated activation energies for coke decomposition were 41.56 and 128.97 kJ/mol for soft and hard coke, respectively, during regeneration. Although the coke in the spent reforming catalyst displayed similar temperature trends for decomposition, the average activation energies were 52.61 and 128.62 kJ/mol for soft and hard coke, respectively. The theoretical results from the multi‐reaction model for coke decomposition are consistent with the experimental results for both catalysts.

Impact of (nano ZnO/multi-wall CNTs) prepared by arc discharge method on the removal efficiency of stable iodine 127I and radioactive iodine 131I from water

Radioactive iodine isotopes especially 131I are used for diagnosis and treatment of different types of cancer diseases. Due to the leak of radioactive iodine into the patient’s urine in turn, the wastewater would be contaminated, so it is worth preparing a novel adsorption green material to remove the radioactive iodine from wastewater efficiently. The removal of 127I and 131I contaminants from aqueous solution is a problem of interest. Therefore, this work presents a new study for removing the stable iodine 127I− and radioactive iodine 131I from aqueous solutions by using the novel nano adsorbent (Nano ZnO/MWCNTs) which is synthesized by the arc discharge method. It is an economic method for treating contaminated water from undesired dissolved iodine isotopes. The optimal conditions for maximum removal are (5 mg/100 ml) as optimum dose with shacking (200 rpm) for contact time of (60 min), at (25 °C) in an acidic medium of (pH = 5). After the adsorption process, the solution is filtrated and the residual iodide (127I−) is measured at a maximum UV wavelength absorbance of 225 nm. The maximum adsorption capacity is (15.25 mg/g); therefore the prepared nano adsorbent (Nano ZnO/MWCNTs) is suitable for treating polluted water from low iodide concentrations. The adsorption mechanism of 127I− on to the surface of (Nano ZnO/MWCNTs) is multilayer physical adsorption according to Freundlich isotherm model and obeys the Pseudo-first order kinetic model. According to Temkin isotherm model the adsorption is exothermic. The removal efficiency of Nano ZnO/MWCNTs for stable iodine (127I−) from aqueous solutions has reached 97.23%, 89.75%, and 64.78% in case of initial concentrations; 0.1843 ppm, 0.5014 ppm and 1.0331 ppm, respectively. For the prepared radio iodine (131I−) solution of radioactivity (20 µCi), the dose of nano adsorbent was (10 mg/100 ml) and the contact time was (60 min) at (pH = 5) with shacking (200 rpm) at (25 °C). The filtration process was done by using a syringe filter of a pore size (450 nm) after 2 days to equilibrate. The removal efficiency reached (34.16%) after the first cycle of treatment and the percentage of residual radio iodine was (65.86%). The removal efficiency reached (94.76%) after five cycles of treatment and the percentage of residual radio iodine was (5.24%). This last percentage was less than (42.15%) which produces due to the natural decay during 10 days.

Bone Char Adsorption of COD and Colour from Tannery Wastewater: Breakthrough Curve Analysis and Fixed Bed Dynamic Modelling

This study delves into the simultaneous adsorption of chemical oxygen demand (COD) and colour from tannery wastewater using bone char through a fixed bed column. The bone char, which was derived from cattle skulls, was characterised using the Fourier transform infrared spectroscopy, Braeuer–Emmett–Teller surface area analysis, and the scanning electron microscope/energy-dispersive X-ray spectroscopy. The effects of different process conditions, specifically, packed bed height (5, 10, and 15 cm) and flow rate (2, 5, and 8 mL/min), on the adsorption efficiency of the fixed bed column were assessed through breakthrough curve analysis. The results revealed that the efficiency of the column bed enhanced with increasing bed height and declined with increasing wastewater flow rate. The optimal operating conditions for COD and colour removal onto the bone char occurred at 15 cm bed height and 2 mL/min flow rate. The adsorption capacities at these conditions were 227.4 mg/g and 53.03 Pt-Co/g for COD and colour, respectively. The kinetics associated with the fixed bed adsorption of COD and colour onto bone char were elucidated through the fitting of the Thomas, Adams–Bohart, and Yoon–Nelson models to the experimental data. Among the three models, the Yoon–Nelson model gave the best prediction of the experimental data. Maximum adsorption efficiencies of 80.65% and 84% were attained for COD and colour removal, respectively, proving that bone char is a promising and ecologically friendly alternative adsorbent for the treatment of tannery wastewater.

Photocatalytic degradation of ciprofloxacin from water with waste polystyrene and TiO2 composites

Ciprofloxacin (CIP) is one of the widely used antibiotics with a broad antimicrobial spectrum in the fluoroquinolone type. Its concentration in water bodies has increased over the years due to its frequent use. Since ciprofloxacin in the aquatic ecosystem adversely affects human health as well as other organisms, it must be removed from wastewater.The aim of this study was to develop Polystyrene (PS) and Titanium dioxide (TiO2) composites that can be used as catalysts in CIP removal by photocatalytic process. Waste PS (obtained from disposable cutlery) was used in the synthesis of these composites. In this study, PS-TiO2 composites with different PS content (C20, C50, C80; the numbers in the names indicate the PS percentage in the composite by weight) were synthesized. This is important in terms of the use of one waste in the removal of another waste.This process was optimized using Box-Behnken design, one of the response surface method. Parameters such as the amount of polymer in the composite, pH and initial CIP concentration were studied and their effects on CIP removal were found. The validity and adequacy of the selected model were evaluated according to the relevant statistical data. These are R2 = 0.9751, adjusted R2 = 0.9565, the model's p-value <0.05 and the lack of fit-value 0.246. Optimum conditions for CIP removal were obtained when the C50 was used, with a pH value of 3 and an initial CIP concentration of 5 mg/L.In the process carried out under these conditions, the CIP removal was found to be 95.01 % at the end of 180 min. This value was predicted as 94.37 % in the model. According to these results, C50 composite synthesized with waste PS can be used effectively for CIP removal.

N-tert-Butoxycarbonyl-N-(2-(tritylthio)ethoxy)glycine as a Building Block for Peptide Ubiquitination.

N-Boc-N-(2-(tritylthio)ethoxy)glycine has been developed as a building block for peptide ubiquitination, which is fully compatible with solid-phase Fmoc chemistry and common peptide modifications including phosphorylation, methylation, acetylation, biotinylation, and fluorescence labeling. The optimal conditions for peptide cleavage and auxiliary removal were obtained. The utility of this building block in peptide ubiquitination was demonstrated by the synthesis of seven ubiquitinated histone and Tau peptides bearing various modifications. Cys residues were well tolerated and did not require orthogonal protection. The structural integrity and folding of the synthesized ubiquitinated peptides were confirmed by enzymatic deubiquitination of a fluorescently labeled ubiquitin conjugate. The synthetic strategy using this building block provides a practical approach for the preparation of ubiquitinated peptides with diverse modifications.

FERRIHYDRITE-CHITOSAN NANOCOMPOSITE AS A RECYCLABLE FLOCCULANT FOR PALM OIL MILL EFFLUENT

In the present study, ferrihydrite-chitosan nanocomposite (FCN) was successfully produced by co-precipitation method and used for the first time as a recyclable flocculant for pre-treatment of palm oil mill effluent (POME). The physicochemical properties of FCN were studied using Raman spectrometer, Scanning Electron Microscope (SEM) and Thermogravimetric Analyser (TGA). The feasibility of FCN to remove total suspended solids (TSS), turbidity, chemical oxygen demand (COD), and, oil and grease (O&amp;G) from POME was investigated using a jar test method. The optimum conditions for contaminant removal from POME were determined by varying the experimental parameters such as flocculant dosage, solution pH and settling time. The results obtained showed that FCN, at a dosage of 1.5 g/L, a contact time of 60 min and pH of 5.0 gave a highest reduction of turbidity, TSS, COD and O&amp;G levels by 72.38%, 77.32%, 71.60% and 53.40%, respectively. Besides that, FCN exhibited a better flocculation performance as compared to alum and chitosan. After three cycles of flocculation/deflocculation process, FCN retained satisfying flocculation efficiency and flocculants recovery in the range of 80-83% and 43.2-78.6%, respectively. Combination of charge neutralisation and polymer bridging was the main key mechanism of interaction between FCN and POME contaminants. The synergy effect between iron oxide/oxyhydroxide nanoparticle and chitosan has increased the physicochemical properties and flocculation performance of the FCN nanocomposite. Overall, FCN nanocomposite can be used an alternative flocculant for POME treatment.