Two-phase olive-oil washing wastewater treatment plus phenolic fraction recovery by novel ion exchange resins process modelling and optimization

Synergistic effects (adsorption and biodegradation) of Streptomyces hydrogenans immobilization on nano-reed biochar for further application in upflow anaerobic sludge blanket

Water pollution due to wastewater is a serious issue that needs to be studied as many organic compounds are released from wastewater, affecting the ecosystem. Therefore, appropriate treatment methods should be used to prevent these effects. Phragmites australis biochar immobilized with bacteria was prepared in this study for use as an adsorbent in a pilot-scale up-flow anaerobic sludge blanket (UASB) to remove organic matter from wastewater in a buffalo farm. Combining reed biochar and immobilized Streptomyces hydrogenans introduces a synergistic effect: reed biochar serves as a substrate for microbial colonization and provides a conducive environment for microbial growth while Streptomyces hydrogenans, immobilized on the biochar, enhances the degradation of organic matter through its metabolic activities. Suitable techniques were employed, including infrared spectroscopy (FTIR) to determine the functional groups before and after adsorption, scanning electron microscopy (SEM) to determine the morphology of the composite before and after adsorption, X-ray diffraction (XRD) to examine the mineralogical changes through reflectometry, high-resolution diffraction and Brunauer-Emmett-Teller (BET) analyses to determine the surface area that always carried out by nitrogen adsorption/desorption technique based on the BET isotherm. Two-level factorial design experiments optimized using biochar, immobilized with bacteria, were employed to enhance the UASB performance. Chemical oxygen demand (COD) removal and biogas production were studied as a function of four experimental parameters: biochar dose, buffalo sludge dose, pH, and bacteria type. The buffalo sludge (manure) dose negatively affected the model's performance. The results showed better COD removal with Streptomyces hydrogenans S11 inoculation. The optimum biochar dose, buffalo sludge dose, and pH were 20 g L-1, 0%, and 7.5, respectively. The COD removal efficiency under these experimental conditions reached 92.70% with a biogas production of 5.0 mL. The experimental results of a validated point from the model were 90.80% for COD removal ratio and 4.80 mL for biogas production at 2 g L-1 biochar dose, 0% buffalo sludge dose, and pH 7.5 using Streptomyces hydrogenans S11 bacteria. A buffalo wastewater (BWW) anaerobic digestion experimental model was best fitted to the data under optimal conditions. This study aligns with the United Nations Sustainable Development Goals (SDGs), specifically SDG 6 (clean water and sanitation) and SDG 12 (responsible consumption and production). The implications of our work extend to large-scale applications, promising a greener and more sustainable future for wastewater treatment.

Role of immobilised Chlorophyta algae in form of calcium alginate beads for the removal of phenol: isotherm, kinetic and thermodynamic study

In this work, sodium alginate-immobilised Chlorophyta algae were evaluated for phenol uptake. The algae/alginate bead (AAB) characteristics were analysed by means of BET-BJH, FTIR, and SEM-EDX methods, while the adsorption performance of AABs with respect to phenol removal was investigated using batch studies. The parameters found to affect the biosorption capacity of AABs included pH, contact time, initial phenol concentration, adsorbent dosage, stirring rate, particle size, and temperature, with the optimal operating variables identified as a pH of 6, an initial phenol concentration of 50 mg/L, AAB dosage of 5 g/L, and a 200 rpm stirring rate. The adsorption process in such cases reached equilibrium within 120 min, demonstrating a maximum phenol elimination capacity of 9.56 mg/g at 30 °C. The isotherm and kinetic models used to determine this were evaluated using the Chi-square test (X²), the coefficient of determination (R²), and the value of equilibrium capacity, with results that revealed that the Freundlich isotherm provides the best fit for the relevant equilibrium data, as shown by its high R² value (0.96) and low X² value (1.16135); the theoretical data produced by that model were thus closer to the experimental data than that from the Langmuir model. Kinetic analysis showed that the phenol adsorption followed a pseudo-second-order kinetic model. The thermodynamic parameters were thus explored, revealing that the phenol biosorption process is based on spontaneous physisorption with an exothermic reaction due to negative (ΔG°) and (ΔH°) values. The low cost, natural origin, biodegradability, and eco-friendliness of algae/alginate bead sorbents also make them ideally suited for phenol removal in aqueous solutions.

Recent advances in polymer composite, extraction, and their application for wastewater treatment: A review

Wastewater from diverse industrial sectors, agricultural practices and other household activities causes water pollution that result in different environmental issues. The main goals of wastewater treatment are typically to enhance the purity of wastewater and to enable the disposal of domestic and industrial effluents without endangering human health or causing excessive environmental issues. There were several natural and synthetic materials which have been utilized for wastewater treatment, amongst them polymers gain more importance due to their non-toxicity, economic feasibility, abundant availability of sources, renewability, biocompatibility, biodegradability, etc. The organic polymers such as cellulose, chitin, gelatin, alginates, lignin, dextran and other starch derivatives are the most commonly used natural polymers in wastewater treatments. The unique physical and chemical characteristics of the natural polymers make them become an alternative in wastewater treatments such as membrane filtration, adsorption, coagulation, flocculation and ion-exchange process to remove harmful contaminants such as toxic metals, dyes, medicines, pesticides, and so on. The review article discusses natural polymers and related uses in wastewater treatment. This review mainly focused on the wastewater treatment using natural polymers and the techniques involved for their extraction from natural sources. The recent trends in polymer extraction from the natural sources and the scope for the future research of natural polymers in various sectors are also discussed in detail.

Polyethylene glycol functionalized reduced graphene oxide coupled with zinc oxide composite adsorbent for removal of phenolic wastewater

The development of agricultural activities and industrialization recently has various adverse impacts on living organisms. The ever-increasing problem of organic pollution has been an environmental concern to the community. Among these, phenolic pollutants like 2,4-dichlorophenol (2,4-DCP), phenol, 2-chlorophenol (2-CP), and bisphenol-A (BPA) are priority toxic pollutants that are continuously released into environment from many industries. In this work, a biocompatible zinc oxide incorporated polyethylene glycol functionalized reduced graphene oxide composite (RGO-PEG-ZnO) was synthesized and explored for the adsorptive removal of toxic phenolic pollutants from water. The optimized adsorption parameters were solution pH 7, adsorption time 60 min, temperature 25 °C, and dosage 0.25 g/L. The isotherms were well fitted by the Langmuir model for BPA and phenol, whereas for 2-CP, and 2,4-DCP, Freundlich was the best-fitted model, and the maximum uptake of BPA, phenol, 2-CP, and 2,4-DCP were 485.756, 511.248, 531.804, 570.641 mg/g, respectively. The kinetic data for all the phenolic pollutants follow the pseudo-second-order model. The thermodynamic analysis shows that Gibb's free energy (ΔG^o) values for all the pollutants were negative, confirming that the process was spontaneous. The positive values of change in enthalpy (ΔH^o) 28.261, 37.205, 46.182, and 61.682 kJ/mol for BPA, phenol, 2-CP, and 2,4-DCP, respectively, confirm that the above adsorption process was endothermic. The composite can be used for up to five cycles with a small reduction in the removal percentage. Adsorption performance of the synthesized composite for synthetic industrial effluents shows that up to 86.54% removal occurred in 45 min adsorption time. Based on the remarkably rapid adsorption and high adsorption capacity, RGO-PEG-ZnO composite can be considered an efficient adsorbent for treating phenolic pollutants from wastewater.

Synthesis of novel epichlorohydrin cross-linked β-cyclodextrin functionalized with reduced graphene oxide composite adsorbent for treatment of phenolic wastewater

A novel composite consisting reduced graphene oxide-functionalized beta-cyclodextrin epichlorohydrin polymer (RGO-βCD-ECH) was synthesized for the treatment of phenolic wastewater. Batch study of phenolic pollutants (2,4-dichlorophenol, 2-chlorophenol, and phenol) was analyzed using the synthesized composite as an adsorbent from an aqueous solution. The optimized parameters were temperature 25 °C, adsorption time 60 min, solution pH 7, and dosage 0.25 g/L. The isotherm data were more suitably fitted by the Langmuir isotherm model. The maximum uptake for 2,4-dichlorophenol, phenol, and 2-chlorophenol was 702.853, 659.475, and 674.155 mg/g, respectively, at 25 ± 1 °C. The kinetic data for all the phenolic pollutants follow the pseudo-second-order model, and the rate was controlled by film diffusion. Thermodynamic data revealed that the process of removing phenolic pollutants is spontaneous and endothermic. The composite can be used up to five cycles with a small reduction in the removal. Adsorption performance of the synthesized composite for synthetic industrial effluents shows that up to 78% removal occurred in 60 min adsorption time. Based on the remarkably rapid adsorption and high adsorption capacity, the synthesized composite can be considered an efficient adsorbent for treating phenolic pollutants from wastewater.

Physicochemical methods for process wastewater treatment: powerful tools for circular economy in the chemical industry

In the chemical industry, a typical problem is the appropriate treatment of the process wastewaters. The biological treatment cannot be usually applied because of the high content of organochemical compounds. However, phsycicochemical methods can significantly contribute to the proper treatment of the process wastewater and usually also allows the recovery of the polluting materials. This phenomenon opens the application area of physicochemical methods for the treatment of process wastewater and can contribute not only to the aims of the circular economy but also to the zero liquid discharge. Besides literature studies, authors’ own results and innovations have been also presented. The treatment strategy for pharmaceutical process wastewater is reviewed in detail, which also serves to point out that hybrid methods can be usually efficient to solve the primary goal–maximum recovery and reuse of polluting materials.

On the modeling and optimization of two-phase olive-oil washing wastewater treatment and polyphenols recovery by ceramic tubular microfiltration membranes

This research is focused on modelling and optimization of the performance of a 'green procedure' based on microfiltration (MF) technology, for recovery of high added-value antioxidant compounds (TACs) from two-phase olive-oil washing wastewater (OOWW) and its treatment. Concern of olive oil industry to improve the production process in line with Circular Economy is vital to make it respectful with the environment including the management of the generated effluents. Key operational factors of the MF process were studied, modelled and optimized by multifactorial statistical analysis. Box-Behnken design was implemented and data analyzed by ANOVA and interpreted by RSM methodology. MF flux was ulteriorly modelled by a second-grade quadratic fitting equation comprising the significant operating variables, being them pressure and tangential velocity. Optimized flow achieved 10962.4 L/hm² at 8.5 bar, 4.2 L/min tangential velocity, ambient temperature (25 °C) and raw pH (5.13). Finally, multiple-response permitted to optimize up to 67% TSS rejection and minimum rejection of TACs of 22.9%, upon 3.57 bar, 4.2 m/s, 23.4 °C and effluent pH of 5.1, meaning the recovery of 77.1% of TACs from OOWW in the permeate stream, up to 1207.1 mg/L. Results show that the proposed process allows a reduction in energy consumption by using the raw effluent with unmodified pH and ambient temperature.