Treatment Of Industrial Effluents Research Articles

Sequentially optimized process towards sustainable synthesis of activated carbon from wild thornbush for 4-nitrophenol and industrial effluent treatment.

Environmental nuisance thornbush Prosopis juliflora was utilized as an inexpensive and renewable biomass raw material for the sustainable production of activated carbon. Previously, the sequential muffle furnace-microwave arrangement was effective with acid activation for activated carbon synthesis. However, the intermediate synthesis steps were not optimized. In this work, we have optimized the intermediate steps, viz. chemical impregnation, carbonization, and microwave activation. Sequential optimization for base activation was developed and compared with acid activation. The base-activated carbon (BAC) exhibited a more crystalline nature and faster uptake kinetics than AAC. BAC demonstrated an adsorption capacity of 576mg/g for 4-nitrophenol (4-NP) surpassing that of optimized acid-activated carbon (AAC) by 45%. The optimal base activation required 1.85 times lower microwave energy than that of the acid activation. BAC exhibited significantly higher BET surface area (1319 m2/g) and micropore volume (0.524 cm3/g) which were about 28% and 26% higher than those of AAC. When compared to biochar obtained from the same thornbush, the BAC exhibited an 11-fold increase in adsorption capacity. The adsorbents could be easily regenerated with ethanol and used up to five cycles. Adsorption using BAC also could achieve 80% COD removal for industrial wastewater, while AAC led to 61% removal. Continuous packed column with BAC revealed a breakthrough time of 3.5h for industrial effluent while for 500mg/L 4-nitrophenol, it was 25h. Prosopis juliflora thornbush, an environmental nuisance, could be converted into a high-capacity adsorbent for environmental remediation after careful sequencing and optimization of the intermediate synthesis steps.

INVESTIGATION OF THE PROPERTIES OF A SORBENT
 OBTAINED BY ACTIVATING PETROLEUM COKE WITH PHOSPHOGYPSUM

The article presents major comparative characteristics of sorbents obtained by chemical activation of petroleum
 coke with phosphogypsum, including the use of polymer binder. The study of sorbents based on phosphogypsumactivated
 petroleum coke for industrial effluent treatment is presented. The article also proposes the flowchart for
 sorbents production on the basis of phosphogypsum-activated petroleum coke with polymer binder, as well as the
 flowchart for using crushed coke for refinery industrial effluent treatment from petroleum and mechanical impurities.

Aqueous Phase Reforming of Dairy Wastewater for Hydrogen Production: An Experimental and Energetic Assessment

The treatment of dairy industry effluents poses a significant challenge from the environmental point of view because of its high organic load. In this work, the aqueous phase reforming of lactose was investigated as a representative model compound for the production of renewable hydrogen. The tests were conducted using two different scenarios: the first one is referred to as direct aqueous phase reforming (APR); the second one proposed a pre-hydrogenation step, followed by APR. The implementation of this reactive pretreatment allowed for minimizing the solid by-product formation with respect to the direct APR, where most of the initial carbon ended up as solid residue. The pre-hydrogenation was investigated in the range of 180–220 °C, using Ru-based catalysts. In the best scenario (using 5% Ru/C), the carbon to solid was reduced by 95%, and up to 70% of the initial carbon was converted into gaseous compounds, hence contributing to the removal of the organic content of the wastewater while producing an energy carrier. Moreover, the hydrogen selectivity increased up to 70% (with respect to 2.5% for direct APR), thanks to hindering homogeneous reaction pathways that do not lead to hydrogen production. Finally, an energetic analysis was conducted to assess the possibility of coupling the APR with the dairy industry and quantifying the percentage of energy which may be produced in situ to satisfy industrial duties.

Influence of industrial effluent treatment ettringite on the compressive and tensile strength and microstructure of soil-cement mixtures

It is increasingly important to find solutions for the problem of the aluminium anodising industry which generates a large amount of acid and alkaline wastewater, composed of high amounts of phosphates, sulphates, nitrates and aluminium. The sulphate removal trough ettringite precipitation is a simple process and involves a low-cost operating. The ettringite can be also formed during the cement hydration in soil-cement mixtures which causes several damages such as expansion. However, the effect of ettringite on the compressive strength, tensile strength and microstructure have few studies. This paper presents a novel experimental study on the influence of the industrial effluent treatment ettringite in resistance and microstructure of soil-cement mixtures. Experimental tests were performed using natural soil, soil mixed with 5% and 6% of cement and soil mixed with 5% and 6% of cement and ettringite for each material. The resistance of the materials was evaluated by unconfined compressive strength and indirect tensile strength, after 3, 7 and 14 days of cure. Additionally, several characterization tests and microstructure analysis were performed. Regarding the experimental results, the compressive strength and tensile strength decreases about 75% and 85%, respectively, when ettringite was added in soil-cement mixtures. The microstructure of natural soil, soil-cement and soil-cement-ettringite mixtures shows that the addition of cement and ettringite, simultaneously, increases the ettringite crystal formation mainly because the cement functions as a source of sulfate ions contributing with the formation of more crystals. Experimental results indicate that the incorporation of ettringite in soil-cement mixtures is not suitable for geotechnical applications.

Distribution of exchangeable cobalt in low-land rice cultivated soils in Sri Lanka as affected by the differences in climate, soil and water source

Cobalt (Co) is considered a beneficial element for plants. However, when soils contain excessive amounts of Co, it could cause phytotoxicity. Despite this, the current status of Co in Sri Lankan rice-cultivated soils is not known. Therefore, this study was conducted to (i) determine the distribution of exchangeable Co concentration, and (ii) examine the interactive effects of climatic zone (CZ), agro-climatic zone (ACZ), soil order, water source, and their interactions in determining exchangeable Co concentration in lowland rice fields in Sri Lanka. A total of 8,292 soil samples representing six ACZs, six soil orders, and three water sources were collected using a stratified random sampling approach. Cobalt was extracted in 0.01 M CaCl2 and measured using Inductively Coupled Plasma Mass Spectrophotometry. Exchangeable Co concentration ranged between 0.03-2,409 μg kg−1 with a mean value of 185.9 μg kg−1. Over 77.5% of the soil samples tested were Co deficient, i.e. <250 μg kg−1. Samples collected from the Intermediate zone, particularly Intermediate zone Mid country, had higher Co concentration than that reported in other ACZs (p<0.05). Among the soil orders, Histosols had higher (232 μg kg−1) and Vertisols had lower (91 μg kg−1) Co concentrations (p<0.05). Moreover, Co concentration was negatively correlated with soil pH (r=−0.3391, p<0.0001) and rice crop productivity (r=−0.1512, p<0.0001). Although exchangeable Co concentration in rice cultivated soils was low, it is important to implement strategies such as proper waste management, treatment of industrial effluents, and the use of safer and more sustainable practices in the chemical and mining industries to minimize further accumulation of Co exceeding the critical limit (i.e. 30 - 40 mg Co kg−1 rice grain), and to ensure the safety of rice production in situations where geological and anthropogenic activities can increase soil exchangeable Co concentration.

Saccharomyces pastorianus Residual Biomass Immobilized in a Polymer Matrix as a Biosorbent for Reactive Dye Removal: Investigations in a Dynamic System.

The use of residual microbial biomass from various industries in emerging pollutant removal strategies represents a new area of research in the field. In this case, we examined how to remove reactive dyes from an aqueous solution utilizing a biosorbent made of residual biomass from immobilized Saccharomyces pastorianus (S. pastorianus) in a polymer matrix using a dynamic system. Fluidized bed column biosorption investigations were carried out on a laboratory scale. Brilliant Red HE-3B was chosen as the target molecule. The main parameters considered for this purpose were the flow rate (4.0 mL/min; 6.1 mL/min), initial pollutant concentration (51.2 mg/L; 77.84 mg/L), and biosorbent mass (16 g; 20 g). The experimental data of the fluidized bed study were evaluated by mathematical modeling. The Yoon-Nelson, Bohart-Adams, Clark, and Yan models were investigated for an appropriate correlation with the experimental data. An acceptable fit was obtained for a flow rate of 4 mL/min, an initial pollutant concentration of 51.2 mg/L, and a biosorbent amount of 20 g. The obtained results indicate that the biosorbent can be used efficiently in a dynamic system both for the removal of the studied dye and in extended operations with a continuous flow of wastewater. As a conclusion, the investigated biocomposite material can be considered a viable biosorbent for testing in the removal of reactive dyes from aqueous environments and creates the necessary conditions for the extension of studies toward the application of these types of biosorbents in the treatment of industrial effluents loaded with organic dyes.

Competitive heavy metal adsorption on pinecone shells: Mathematical modelling of fixed-bed column and surface interaction insights

Pinecone shells are assessed as a cost-effective biosorbent for the removal of metal ions Pb(II), Cu(II), Cd(II), Ni(II), and Cr(VI) in a fixed-bed column. Influent concentration, bed height, and flowrate are studied to improve efficiency. The breakthrough data is well fitted by the Sips adsorption model, suggesting a surface complexation mechanism, with maximum adsorption capacities of 11.1 mg/g for Cu(II) and 66 mg/g for Pb(II).In multimetal solutions, the uptake sequence at breakthrough and saturation is Pb(II) > Cu(II) > Cd(II). Characterization via FTIR and XRD reveals carboxyl and hydroxyl functional groups interacting with metal ions. Ca(II) does not compete with Pb(II), Cu(II), and Cd(II) adsorption, highlighting the ability of pinecone to adsorb heavy metals via surface complexation. Its application in the treatment of industrial effluents containing Cu(II), Ni(II), and Cr(VI) is explored.The study investigates bed media regeneration via eluting adsorbed metal ions with hydrochloric acid solutions. The potential of pinecone shells as an efficient biosorbent for removing toxic metal ions from industrial wastewater is emphasized. These findings enhance our understanding of the adsorption mechanism and underscore the fixed-bed column system's applicability in real-world scenarios, addressing environmental concerns related to heavy metal contamination of industrial effluents.

Tailoring magnetic Sn-MOFs for efficient amoxicillin antibiotic removal through process optimization.

This study investigated the efficacy of magnetic Sn metal-organic frameworks (MSn-MOFs) in removing the insecticide amoxicillin (AMX) from aqueous solutions. Our thorough experimental investigation showed that MSn-MOFs were an incredibly effective adsorbent for removing AMX. Several methods were used to characterize the material. BET investigation of the data displayed a significant surface area of 880 m2 g-1 and a strong magnetic force of 89.26 emu g-1. To identify the point of zero charge, surface characterization was carried out and the value was 7.5. This shows that the adsorbent carries a positive and negative charge below and above this position, respectively. Moreover, the impact of pH on adsorption equilibrium was explored. The results of kinetic models to explore the adsorption of AMX on MSn-MOFs supported the pseudo-second-order, and the adsorption complied well with the Langmuir isotherm. The results revealed that the overall adsorption mechanism may entail chemisorption via an endothermic spontaneous process with MSn-MOFs. The precise modes by which MSn-MOFs and AMX interacted may involve pore filling, H-bonding, π-π interaction, or electrostatic interaction. Determining the nature of this interaction is essential in understanding the adsorption behavior of the MOFs and optimize the adsorbent design for real-world applications. The use of the MSn-MOF adsorbent provides a straightforward yet efficient method for the filtration of water and treatment of industrial effluents. The results showed 2.75 mmol g-1 as the maximum capacity for adsorption at pH = 6. Additional tests were conducted to assess the adsorbent regeneration, and even after more than six cycles, the results demonstrated a high level of efficiency. The adsorption results were enhanced by the application of the Box-Behnken design.

Hydrothermal metal recovery of metal-contaminated wastewater with forest residue: a zero waste discharge process

This study demonstrates a zero-waste discharge, hydrothermal treatment of industrial metal effluent infused with agricultural waste for co-generation of a hydrogen-rich gas mixture and nanometal carbon composites for diverse applications.

Prediction of the removal of solid suspensions and chemical oxygen demand from a pharmaceutical wastewater plant using a neural network approach

This study aimed to model the removal efficiency of chemical oxygen demand (COD) and solid suspension (SS) from a real pharmaceutical wastewater treatment plant (WWTP) using artificial neural network-multilayer perception (ANN-MLP). The ANN model was developed using experimental data which were collected during four years. The input variables of the neural network are water pH, temperature, SS, and COD. The percentages of removal of COD (CODRE) and of SS (SSRE) are considered as output variables. The Levenberg–Marquardt algorithm was utilized to train ANN. It was found that the ANN architecture has two hidden layers with 8 neurons. The results of ANN models were compared with the measured data based on the correlation coefficient (R2) and mean square error (MSE). It was noticed that the best ANN model provides good accurate results with R2 values of 0.9783 for SSRE and 0.9826 for CODRE, and a value of MSE equal to 1.695 10−3. This study may aid the users to adjust operational parameters in recovering COD and SS in the case of the process treatment of industrial effluents.

Creation of an environmental complex for the finishing of water facilities in oil fields

The aim of our study is to find solutions for reducing anthropogenic stress from oil and petroleum products pollution in oil production areas. To this end, it is proposed to establish an environmental facility for the treatment of water bodies. The climatic conditions and experience of the application of purification complexes in the conditions of the Far North should be considered. Conduct an analysis of the quality of water bodies and existing pollution at present. Based on the analysis, design an environmental complex to clean water from oil and petroleum products. The Environmental Complex will implement a phased clean-up of water bodies. The technology is based on natural mechanisms of transformation of technogenic water bodies into a natural ecosystem to improve the efficiency of industrial effluent treatment. The ecosystem will consist of gabion structures, innovative phytopulvers for optimal conditions for plant growth and development. Phyto Modules have a simple design. The proposed technology will improve water pollution and improve the ecology of our region.

Removal and adsorption kinetics of methylene blue dye by pristine cotton husk bracts (Gossypium hirsutum L.) from agroindustrial waste

In the present study, pristine cotton husk bracts (CHk), an agricultural waste, were successfully employed as an adsorbent for the removal of methylene blue (MB). Batch adsorption experiments were performed as a function of contact time, pH, adsorbent dosage, and initial dye concentration (1–100 mg/L). The experimental results indicate that 20 mg of CHk removed 94% of 20 mg/L dye. Adsorption dye kinetic was analyzed using pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. Furthermore, adsorption data were modeled using the Langmuir, Freundlich, and Temkin isotherms. The kinetic study reveals that the present adsorption process followed a pseudo-second-order, with a qe= 96.56 mg/g and, k2 = 0.109 min−1 at pH 7. Adsorption followed the Langmuir isotherm; the adsorption equilibrium results show a qm = 458.72 mg/g and kL= 0.1622 L/mg, using 20 mg of CHk. The equilibrium parameter value (RL) was observed to be in the interval of 0.0580 to 0.8604. Thermodynamic results indicate that the adsorption mechanism between CHk and MB is spontaneous, exothermic, and with a decrease in the disorder of the adsorbate molecules on the adsorbent surface; at all the temperatures studied (293, 313, 333 K). The use of CHk agroindustrial waste is an ideal option for the treatment of industrial textile effluent in environmental cleansing.

Ecology treatment of a real industrial effluent with chitosan: Characterization and design of coagulation-flocculation process

Coagulation-flocculation (C-F) process is frequent in treating industrial wastewater. Coagulants and flocculants are mostly inorganic, but these products can cause serious ecological problems. Chitosan (QS) is considered effective in this process and is friendly to the environment. The objective of the work was to study the treatment of a real effluent from the graphic industry using C-F with chitosan and project the design of an agitated industrial system. For effluents with low Total solid, the optimal dose of QS is near 7.81 mg/L, while for larger content of Solid, it is 31.3 to 62.5 mg/L. The pH that favours this process is between 6-7. A working temperature of 25 °C also benefits the sedimentation treatment. QS additions generate laboratory-scale solids sedimentation after 5 minutes. At 20 minutes, a significant reduction in UV-Visible absorbance is observed.

Four-in-one strategy to boost the performance of 3-dimensional MoS2 nanostructures for industrial effluent treatment and hydrogen evolution reactions

Two-dimensional (2D) molybdenum disulfide (MoS2) has gained enormous attention as a photocatalytic material due to its extraordinary optical, electrical, and chemical properties which are highly tunable by engineered control of its 2D layers orientation. However, high carrier recombination rates in pristine MoS2 nanostructures hinder their practical applications as an efficient catalyst. There is an upsurge of research on developing new strategies to improving its photocatalytic actions for environmental remediation. One approach is to design MoS2 nanostructures with vertically aligned layer-structures or cross-linking 3-dimensional flower-like morphologies, which exhibit ultrahigh-density 2D edge sites that offer tremendous chemical reactivity. Another challenge is to obtain its highly active metallic 1 T phase by functional design of intrinsic structures without sacrificing its ambient stability. Herein, we reported highly active and mix-phased 1 T/2 H MoS2 nanostructures through elegant synthesis management. By regulating reaction kinetics with the assimilation of NH4+ ions and water molecules, tunable surface morphology from nano wrinkles to nanoflowers was achieved. The morphology regulations induced modifications in the surface areas of final products which were calculated as 64.3 m2g−1, 114.3 m2g−1, and 219.7 m2g−1, respectively. Moreover, the bandgaps were significantly lowered from 2.13 eV to 1.93 eV and 1.85 eV. This four-in-one strategy efficiently boosted photodegradation of organic pollutants up to 94% in less than 20 min with excellent cyclic reproducibility for seven cycles. In addition, exceptional hydrogen evolution reaction (HER) performance with a very low overpotential of 145 mV and Tafel slope of 81.4 mV/dec was recorded. The results obtained in this work demonstrated excellent suitability of these materials as catalysts in environment related applications such as organic dye removal and for efficient hydrogen production.

PI nanofiber membranes with pH-responsive wettability fabricated through solution blow spinning for efficient on-demand oil-water separation

Nanofiber membranes (NFMs) are widely used in oil-water separation area due to their unique structure and properties. However, achieving efficient and on-demand separation of oil-water mixtures using NFMs remains a challenge. Herein, we prepared polyimide nanofiber membranes (PI-NFMs) with fluffy structures through solution blow spinning (SBS), and the average diameter of the PI nanofibers was 506.1 ± 75.6 nm. The PI-NFMs exhibited excellent pH responsiveness, demonstrating the ability to swiftly convert their wetting properties between highly hydrophobic and superhydrophilic through a simple acid-alkali treatment. Additionally, the conversion between oil removing model and water removing model according to the type of oil-water mixture was realized. The performance of the membranes in separating oil and water was evaluated using five different densities of oil-water mixtures. Only driven by gravity, the membrane exhibits good separation efficiency and extremely high permeate fluxes with the water and oil fluxes to 37,641.84 and 71,083.16 L·m−2·h−1, respectively, which also shows decent reusability. This work presents a promising solution for the intelligent, efficient, and controllable treatment of industrial oil effluents and oil spills.

Food Industrial Effluent Treatment with Oxygen and Ozone Using Activated Carbon for Catalytic Oxidation

ABSTRACT A catalytic oxidation treatment to remove coloration and chemical oxygen demand (COD) in an effluent from a food industry was carried out using oxygen and ozone as oxidizing agents and activated carbon as a catalytic. Different experiments of oxidation were conducted using 25, 50 and 100 mL of activated carbon bed to treat 100 mL of sample and constant flow of oxygen 7.2 g/min and ozone 0.034 mg/min, maintaining initial pH of industrial effluent. Almost a complete coloration removal and COD reduction of the sample was achieved for catalytic processes; however, time of treatment and agent oxidant doses were different in each case. According to volume of activated carbon beds, ozone doses for discoloration and COD removal were 8.5, 2 and 1.7 mg/L, whereas the oxygen doses were 2860, 770 and 500 g/L, respectively. Consequently, to eliminate the color in the industrial effluent, the dose of oxygen was higher than that of ozone. In addition, the oxidation agents promoted the regeneration of activated carbon, showing that its activity is declined after 60 cycles of effluent treatment with ozone, whereas with oxygen treatment, the total depletion was observed in 18 cycles. In turn, single adsorption showed activated carbon depletion in 5 cycles of effluent treatment.

Machine learning algorithm and neural network architecture for optimization of pharmaceutical and drug manufacturing industrial effluent treatment using activated carbon derived from breadfruit (Treculia africana)

In a recent development, attention has shifted to the application of artificial intelligence for the optimization of wastewater treatment processes. This research compared the performances of the machine learning (ML) model: random forest, decision tree, support vector machine, artificial neural network, convolutional neural network, long-short term memory, and multiple linear regressors for optimization in effluent treatment. The training, testing, and validation datasets were obtained via the design of an experiment conducted on the removal of total dissolved solids (TDS) from pharmaceutical effluent. The breadfruit-activated carbon (BFAC) adsorbent was characterized using scanning electron microscopy and X-ray diffraction techniques. The predictive capacity of an ML algorithm, and neural network architecture implemented to optimize the treatment process using statistical metrics. The results showed that MSE ≤ 1.68, MAE ≤ 0.95, and predicted-R2 ≥ 0.9035 were recorded across all ML. The ML output with minimum error functions that satisfied the criterion for clean discharge was adopted. The predicted optimum conditions correspond to BFAC dosage, contact time, particle size, and pH of 2.5 mg/L, 10 min, 0.60 mm, and 6, respectively. The optimum transcends to a reduction in TDS concentration from 450 mg/L to a residual ≤ 40 mg/L and corresponds to 90% removal efficiency, indicating ± 1.01 standard deviation from the actual observation practicable. The findings established the ML model outperformed the neural network architecture and affirmed validation for the optimization of the adsorption treatment in the pharmaceutical effluent domain. Results demonstrated the reliability of the selected ML algorithm and the feasibility of BFAC for use in broad-scale effluent treatment.

Sonocatalytic degradation of nitrobenzene with metal oxide clay nanocomposites

AbstractBACKGROUNDThe presence of a wide range of persistent toxic organic pollutants in industrial effluents poses a serious threat to human and environmental health, emphasising the necessity for developing cost‐effective methods for treating toxic effluents. This study focuses on the synthesis, characterization and evaluation of metal oxide [iron (Fe), copper (Cu) and zinc (Zn)]‐doped clay composite for the sonocatalytic degradation of nitrobenzene (NB) in the presence of ultrasound.RESULTS AND CONCLUSIONSAmong the metal oxides studied, Cu and Fe oxide‐modified clay performed better in the degradation of NB (~99% in the presence of air) compared to a ZnO/clay composite. Process optimization studies were carried with CuO/clay composite at different pHs (2.5–11.5), feed concentrations (50–200 mg L−1) and catalyst loadings (0.25–1.0 g L−1). Neutral pH conditions and higher catalyst loadings of 1 g L−1 were found to be optimal for the efficient degradation of 50 ppm NB. Among the scavengers tested, ethylenediamine tetra acetic acid exhibited strong scavenging effects, resulting in reduced NB degradation compared to isopropyl alcohol and tin tetrachloride, regardless of the scavenger concentration (0.5 and 40 mmol L−1). The catalyst was found to be sufficiently stable for up to four cycles under identical conditions. Additionally, these materials were found to be effective in the degradation of other pollutants [Terephthalic acid, Rhodamine‐B, Ciprofloxacin]. These findings contribute to the development of cost‐effective strategies for the treatment of industrial effluents, reducing the risks posed to both the environment and human health. © 2023 Society of Chemical Industry (SCI).

Bioremediation of Cr(VI) using indigenous bacterial strains isolated from a common industrial effluent treatment plant in Vishakhapatnam

Abstract The present study focuses on removing hexavalent chromium (Cr(VI)) using indigenous metal-resistant bacterial strains isolated from a common industrial effluent treatment plant, a contaminated site in Vishakhapatnam. Three high metal-resistant isolates were screened by growing them in nutrient agar media containing different Cr(VI) concentrations for 24 h at 35 ± 2 °C. The three strains’ minimum inhibitory concentrations of Cr(VI) were examined at neutral pH and 35 ± 2 °C temperature. Morphological, biochemical, and molecular characterizations were carried out, and the strains were identified as Bacillus subtilis NITSP1, Rhizobium pusense NITSP2, and Pseudomonas aeruginosa NITSP3. Elemental composition and functional group analysis of the native and metal-loaded cells were done using energy-dispersive spectroscopy and Fourier-transform infrared spectroscopy, respectively. The operating conditions were optimized using a one-factor-at-a-time analysis. When compared with three bacterial isolates, maximum Cr(VI) removal (80.194 ± 4.0%) was observed with Bacillus subtilis NITSP1 with an initial Cr(VI) concentration of 60 mg/L, pH 7.0, an inoculum size of 2% (v/v), and an incubation period of 24 h. The logistic model was used to predict the variation of biomass growth with time. The present study can be extended to remove heavy metals from industrial wastewater in an environmental-friendly manner.

Potential of electrocoagulation technology for the treatment of tannery industrial effluents: A brief review

Potential of electrocoagulation technology for the treatment of tannery industrial effluents: A brief review