Application In Wastewater Treatment Research Articles

A comparative study on the treatment of kitchen grey water using microalgae consortia and microalgae-synthesized silver nanoparticles.

Comparative study on the potential of microalgae consortia and green-synthesized silver nanoparticles using microalgae (M-AgNP) consortia for the treatment of kitchen grey water was investigated in this study. The microalgae consortia consisting of four species, viz., Chlorella sp., Scenedesmus sp., Coelastrum sp., and Pediastrum sp. were isolated from a local fish pond and the silver nanoparticles were synthesized with the same. Thus, synthesized silver nanoparticles exhibited a distinctive yellowish-brown colour and spherical morphology. Extensive qualitative and quantitative characterization techniques were employed to determine their size and morphology. Both microalgae consortia and M-AgNP were used separately for the treatment of kitchen grey water under experimental conditions. The synthesized silver nanoparticles demonstrated promising potential for domestic wastewater treatment, leading to substantial reductions in various parameters: total dissolved solids (29.6%), conductivity (49.4%), chemical oxygen demand (64.6%), and heavy metals (arsenic-63.5%, zinc-45.6%, cadmium-88%, copper-60.52%, and lead-80.82%). Notably, microalgae exhibited superior removal efficiency for nitrate (83.1%), sulphate (70.3%), and phosphate (96.5%) compared to microalgae-synthesized silver nanoparticles. This study underscores the effective utilization of both microalgae and microalgae-synthesized silver nanoparticles for wastewater treatment applications.

Poly(vinylpyrrolidone) mediated synthesis of TiO2 with enhanced photocatalytic activity and stability

Improving photocatalytic activity and stability of titanium dioxide (TiO2) is crucial for its application in wastewater treatment. Incorporating polymer ligands into the synthetic process is an important way to improve the catalytic performance of TiO2. In this work, a water-soluble, non-toxic, and non-ionic polymer, polyvinylpyrrolidone (PVP), was used to regulate the synthesis of TiO2 by using hydrothermal method. It was observed that PVP-regulated TiO2 had enhanced photocatalytic performance comparing with the pure TiO2, mainly due to the enhanced light absorption, the suppressed charge recombination efficiency, the increased oxidation power of photogenerated holes and specific surface area. Additionally, the catalytic stability of the catalyst was also improved. As a result, TiO2 assisted with PVP exhibited a significant improvement in catalytic stability after four cycles of methyl orange degradation. Our research results can provide experimental and theoretical basis for the development of photocatalysts with excel-lent stable catalytic performance.

Sustainable Sol‐Gel Approach for Visible Light‐Responsive Titanium Dioxide Nanoparticles in Efficient Diazinon Removal

AbstractThis study addresses water pollution challenges by employing photocatalysis as an effective solution. Titanium dioxide (TiO2) with unique characteristics is widely utilized in this approach. However, the design of nanosized TiO2 particles is crucial for enhancing photocatalytic performance during diazinon's photodegradation. As such, the TiO2 nanoparticles (NPs) were synthesized via the green sol‐gel method in this study, exhibit a mixed anatase‐brookite phase, a small particle size of 11.17 nm, and lower bandgap energy (3.00 eV) than pure anatase TiO2 of 3.20 eV, rendering them active under visible light. DFTB calculation was deployed to investigate the role of oxygen vacancies in reducing the bandgap energy. Experimentally measured (3.00 eV) and computationally (2.812 eV) determined bandgap energies align well. The TiO2 NPs demonstrate significant photocatalytic efficacy, degrading 73.3 % of diazinon within 210 min under sunlight, with a mineralization degree of 43.50 %, and 2‐isopropyl‐6‐methylpyrimidin‐4‐ol (IMP) was detected as the intermediate product. The photodegradation follows first‐order kinetics, and adsorption isotherm analysis fits the Langmuir model. ⋅O2− is identified as the predominant reactive oxygen species in the diazinon's photodegradation. Hence, the synthesized TiO2 NPs offer good reusability, maintaining a degradation efficiency of 67.4 % even after five cycles, showing good potential for wastewater treatment applications.

Electrospinning nanomaterials: a powerful strategy for wastewater treatment applications

Electrospinning nanomaterials: a powerful strategy for wastewater treatment applications

An attempt to augment performance of machine learning models in a pilot-scale urban wastewater treatment system

The challenge we face is striking a balance between ensuring the standards for wastewater treatment processes and minimizing energy consumption. As such, accurate predictive models become critical. With machine learning algorithms having the ability to discern relationships between inputs and outputs, broad interest has been shown in their applications in wastewater treatment. A key research focus is on effectively adjusting these generic machine learning algorithms to adapt to frequent fluctuations of water quality, inflow volume, and environmental variations. This study developed a Nonlinear Autoregressive neural network (NARX) model having an adaptive real-time updating module to predict the ammonium concentration in the treated effluent. The model has exhibited high predictive accuracy on the testing data, achieving an R2 value of 0.997. By incorporating an adaptive real-time updating module, the model's capability to predict effluent ammonium concentration on novel data sets has been significantly improved, with the R2 value for these predictions increasing from an initial 0.918 to a more refined range of 0.966 to 0.984. Our findings confirm that integrating real-time updating capabilities with machine learning algorithms substantially improves the stability and predictive performance of the models. These outcomes will prompt a broader integration of artificial intelligence in the domain of environmental engineering, which shall foster the implementation of more accurate and eco-friendly wastewater treatment strategies.

Adsorption Properties of the Alkalized Accordion‐Like Ti3CN MXene for Pb(II) Ion

AbstractThe presence of poisonous Pb(II) ions in water resources has raised global health concerns. Herein, the adsorption performance of accordion‐like Ti3CN MXene for Pb(II) ions was investigated for the first time. Batch experiments were carried out by varying modifications, pH values, initial Pb(II) concentrations, adsorption time and temperatures. The results prove that the alkalized‐Ti3CN shows enhanced adsorption performance. Although the temperature effect is insignificant, the Pb(II) adsorption is strongly pH‐dependent. The maximum Pb(II) adsorption capacity of alkalized −Ti3CN is about 2.5 times higher than that of activated carbon. The adsorption ratio of Pb(II) is up to 96.6 %. The adsorption capacity increases with increasing the initial concentration of Pb(II). The alkalized‐Ti3CN adsorbs Pb(II) very quickly and the adsorption equilibrium is nearly achieved within 70 minutes. The adsorption follows the quasi‐second‐order kinetic model as well as the Langmuir model, and is mainly controlled by chemical adsorption. It is preliminarily concluded that Pb(II) replaces Na(I) of the −ONa functional groups on the alkalized‐Ti3CN surfaces. This study proves the alkalized‐Ti3CN MXene has potential application for the purification treatment of wastewater contaminated with Pb(II) ions.

Assessing the Lead Removal Potential of Pineapple Waste Hydrochar in Simulated Wastewater Treatment

This study explores the viability of utilizing biochar and hydrochar derived from pineapple waste as adsorbents for removing lead (Pb) from water. Pineapple residues, including stems, leaves, and fruit, were subjected to pyrolysis and Hydrothermal Treatment to produce biochar (PWB) and hydrochar (PWH) respectively. Fourier Transform Infrared (FT-IR) analysis was employed to characterize the surface properties of PWB and PWH, validating their potential as adsorbents. A series of adsorption experiments assessed the impact of pH (ranging from 2 to 6), contact time (ranging from 15 to 90 minutes), and temperature (ranging from 30 to 90°C) on the adsorption efficiency of both materials. Results indicate PWH to be markedly more effective, with an average Pb removal efficiency of 84.07% compared to PWB's 55.68%. The optimal contact time was determined to be 60 minutes for both materials. Moreover, pH 4.0 was identified as the optimal condition for Pb adsorption, showcasing a significant increase in biosorption capacity within this pH range. Additionally, higher temperatures corresponded to enhanced Pb2+ removal efficiency, rising from 75.02% to 87.58% as temperature increased from 30°C to 90°C. Overall, these findings underscore the potential of pineapple waste-derived biochar and hydrochar as promising, environmentally friendly adsorbents for addressing heavy metal contamination in water, particularly in wastewater treatment applications.

Analysis of Ag-DP25/PET plasmonic nano-composites as a visible-light photocatalyst for wastewater treatment: Experimental/theoretical studies, and the DFT-MB degradation mechanism

The development of polymeric-composites Agx%DP25-PET (x = 0,1,2,3) may significantly boost the potential application of Agx%DP25 (x = 0,1,2,3) photocatalytic powders. Producing large-scale nano-composites with hybrid-surfaces, that are also flexible materials and easy to employ in a variety of environments. A set of photocatalytic nan-composites embedded with the polymeric binder poly (acrylonitrile-co-butadiene)-dicarboxy terminated (C7H9N) were performed and evaluated for wastewater treatment applications. The results reveal that the flexible polymeric composites (Agx%DP25-PET, x = 0,1,2,3) have photocatalytic activity in aqua media to degrade methylene blue (MB) under visible-light. The addition of C7H9N to immobilize photocatalytic powders on the PET surface reduces photo-generated electron-hole recombination. The materials were characterized by HR-TEM, SEM/EDX, XRD, FT-IR, UV–Vis DRS and PL. The Agx%DP25-PET (x = 0,1,2,3) photocatalytic reactions exhibited productive discoloration/degradation rates, in both aerobic (AE) and anaerobic (AN) environments. The superior photodegradation of Ag2%DP25-PET was attributed to a combination of two effects: LSPR (localized surface plasmon resonance) and Ag–TiO2/environment affinities. The findings of molecular dynamics (MD) simulation and Fukui Function (FF) based on density functional theory (DFT) provide significant insight into the photocatalytic requirements for MB discoloration/degradation. The experimental/theoretical analysis aimed to offer an in-depth understanding of medium/surface interactions on decorated TiO2 materials, as well as how these interactions affect overall degradation behavior.

Unlocking the superior flexibility and enhanced catalytic oxidation performance of CoTiO3 nanofibrous membranes through zirconium doping

The development of continuous CoTiO3 (CTO) fibers with prominent catalytic oxidation activity, tunable fibrous structures, and improved recyclability is appealing for application in efficient organic wastewater treatment; however, inescapable flaws remain, such as their inherent brittleness and adverse operability. Herein, a facile and effective strategy is proposed for the fabrication of flexible and mechanically robust CTO nanofibrous membranes through a combination of element doping and sol–gel-assisted electrospinning. Compared with pristine CTO fibers, the resulting zirconium-doped CoTiO3 (ZCTO) nanofibrous membranes displayed remarkably enhanced flexibility and tensile mechanics, which were attributed to their lower crystallinity, smaller grain size, and fewer fiber surface defects. The developed ZCTO fibrous membrane demonstrated exceptional resistance to bending fatigue, retaining a polymer-like bending rigidity of approximately 25 mN even after undergoing 200 reciprocating bending cycles. Furthermore, the incorporation of zirconium into CTO clearly had an advantageous effect on the formation of oxygen vacancies, thereby enhancing the surface adsorption of peroxymonosulfate (PMS), accelerating the electron transfer process, and weakening the peroxy bonds. The tetracycline degradation efficiency of the ZCTO fibers remained at 81.4% within 10 min after 5 continuous cycles. Benefiting from their robust mechanical properties and excellent catalytic activity, the fabricated membranes demonstrated outstanding dynamic catalytic performance under gravity-driven conditions. More importantly, the reported strategy might be adopted and extended to develop a wide range of ceramic fibers with enhanced flexibility and mechanics for catalytic oxidation.

Activation of peracetic acid by a magnetic biochar-ferrospinel AFe2O4 (A = Cu, Co, or Mn) nanocomposite for the degradation of carbamazepine − A comparative and mechanistic study

Peracetic acid (PAA)-based advanced oxidation processes (AOPs) are promising technologies for the efficient treatment of persistent contaminants in wastewater. In this study, three different magnetic biochar (BC)-ferrospinel AFe2O4 (A = Cu, Co, or Mn) nanocomposites were synthesized through a combined sol–gel/pyrolysis process for the activation of PAA to degrade carbamazepine (CBZ). The following order of efficiency was observed for CBZ degradation in the presence of PAA: BC-CoFe2O4 (100 %) > BC-MnFe2O4 (7 %) ≈ BC-CuFe2O4 (7 %). In addition, 0.8 mM PAA, 0.3 g/L catalyst, nearly neutral pH, and 333 K were identified as the optimal operating parameters for the degradation of 1 mg/L CBZ in the BC-CoFe2O4/PAA system. Mechanistic studies revealed that CH3C(O)OO radicals are the dominant active species for the degradation of CBZ in the BC-CoFe2O4/PAA system, and the continuous conversion of Co(II) to Co(III) in this system is responsible for the generation of these radicals. In addition, the water matrices (e.g., humic acid (20 mg/L), NaCl (0.05 M), and NaNO3 (0.01 M)) played negligible roles in the degradation of CBZ in the BC-CoFe2O4/PAA system. This system exhibited highly selective and reactive degradation of organic pollutants with electron-rich groups (e.g., CBZ (0.36 min−1), sulfamethoxazole (0.12 min−1), and diclofenac (0.28 min−1)). Furthermore, the degradation products of CBZ were identified, and possible degradation pathways and toxicity of these transformation products were proposed. The BC-CoFe2O4/PAA system demonstrated outstanding degradation performance in dynamic systems and real wastewater treatment applications. This study describes the performance of an efficient and easy-to-separate catalyst for the activation of PAA. This study facilitates the development and application of PAA-based AOPs for wastewater treatment.

Preparation of dopamine/L-cysteine modified PVDF composite membrane and its application in the removal of mercury ions from water

Polyvinylidene fluoride (PVDF), embodying a stabilization under thermal environment and capability to resist chemical corrosion, is widely used as a membrane-forming material. However, its inherent hydrophobicity and lack of active functional groups in the structure limit its suitability for adsorption applications. In this study, PVDF-based membranes were first prepared by the non-solvent phase inversion method, and then, polydopamine (PDA) was coated on these membranes by the oxidative self-polymerization of dopamine (DA). Then, L-cysteine (LCys) was grafted by self-assembly to obtain a highly hydrophilic PVDF composite (PVDF@PDA-LCys) membrane with excellent ability for Hg(II) ion capture. The membrane has the following characteristics: excellent hydrophilicity, with a water contact angle (WCA) that drops to 0° within 3s, which is far superior to the 89.22° WCA of the PVDF-based membrane. Given an 10mg·L-1 initial concentration of Hg(II), adsorption experiences 120min, the removal efficiency reaches 95.14%. The fitted maximum adsorption capacity is 97.98mg·g-1. Additionally, the composite membrane exhibits good acid resistance. When the solution pH is as low as 1.5, the Hg(II) ion removal efficiency is still close to 70%. The performance of the composite membrane remains stable after repeated use. This study demonstrates an environmentally friendly and practical method for preparing PVDF-based composite membranes with potential applications in wastewater treatment.

Green synthesis of silver nanoparticles decorated on graphene oxide for crystal violet dye removal

In this study, we demonstrate a facile and environmentally benign method for the synthesis of Ag nanoparticles using a green reducing agent and their subsequent deposition onto GO sheets. The synthesized GO@Ag nanocomposite was characterized using various analytical techniques such as FTIR, XRD, FESEM, EDX and BET. The results confirmed the successful formation of cubic Ag nanoparticles with diameter 30–40 nm on the GO surface. The theoretical surface area of GO@Ag was found to be 89 m2/g. The adsorption efficiency of GO@Ag nanocomposite toward CV dye was evaluated through batch adsorption experiments. The above experimental results revealed that CV adsorption on to the GO@Ag surface was pH dependent and maximum adsorption capacity was found to be 48.78 mg/g at pH = 8. The adsorption process followed pseudo-second-order kinetics and Langmuir isotherm models, indicating monolayer adsorption with chemisorption as the rate-limiting step. Furthermore, the recyclability and stability of the nanocomposite were assessed through multiple adsorption-desorption cycles, demonstrating its potential for practical applications in wastewater treatment for the removal of cationic dyes. The mechanism of CV adsorption on to the GO@Ag surface mainly involves electrostatic attraction and π-π interaction.

A novel synthesis method of magnetic Janus particles for wastewater applications

HypothesisMagnetic particles are widely used in many adsorption and removal processes. Among the many types of magnetic colloids, magnetic Janus particles offer significant possibilities for the effective removal of several components from aqueous solutions. Nevertheless, the synthesis of structures integrating different types of materials requires scalable fabrication processes to overcome the limitations of the available methodologies. Herein, we hypothesized a fabrication process for dual-surface functionalized magnetic Janus particles. ExperimentsThe primary silica particles with surface-attached amine groups are further asymmetrically modified by iron oxide nanoparticles, exploiting Pickering emulsion and electroless deposition techniques. The dual surface functionality of the particles is designed for its versatility and demonstrated in two wastewater-related applications. FindingsWe show that our design can simultaneously remove chromium (VI) and phenol from aqueous solution. The fabricated magnetic-responsive Janus particles are also an effective adsorbent for genomic Deoxyribonucleic acid (DNA) and show superior performance to commercial magnetic beads. Thus, this study provides a novel platform for designing magnetic Janus particles with multifunctional surfaces for wastewater treatment applications.

Thermodynamic study and the development of a support vector machine model for predicting adsorption behavior of orange peel-derived beads in wastewater treatment

This study investigates the use of orange peels as a precursor for synthesizing sodium alginate-encapsulated beads for methylene blue (MB) removal. The prepared beads (BOP1 and BOP2) underwent characterization through FTIR, XRF, SEM and TGA. Subsequently, the impacts of various factors, including temperature, the initial pH, initial concentration, salt and humic acid, are studied. The adsorption isotherms show high adsorbed quantities of 764.92 and 659.78 mg/g for BOP1 and BOP2 respectively, while the obtained data are best described by the monolayer with two energies (MMTE) model, which is then used to perform a thermodynamic study of the MB adsorption mechanism. Additionally, the adsorption kinetics data are modeled using three models, with the PFO model identified as the most appropriate. The regenerated beads demonstrate the ability to be reused up to 7 cycles, The effects of NaCl and humic acid on MB adsorption reveal that NaCl inhibits adsorption due to competition with Na+, while humic acid has no effect. Finally, a support vector machine (SVM) model optimized by the Levy Flight Distribution Optimization (LFD) algorithm is developed and found to be capable of accurately predicting the adsorption behavior of the prepared beads. This model is then used in optimizing the process conditions for maximal MB removal. Overall, this study demonstrates that the prepared beads could be potential low-cost and environmentally friendly adsorbents for wastewater treatment applications.

Efficient Removal of Methylene Blue and Methyl Red Dyes Using a Novel Adsorbent Derived from Saponaria Officinalis Root via H3PO4, H2SO4, and KOH-Activation: Optimization, Kinetics, and Isotherm Study

This study focuses on the optimization, kinetics, and isotherms of a novel adsorbent derived from Saponaria Officinalis root for efficient removal of methylene blue and methyl red dyes. The preparation of the activated carbon involved specific parameters such as activating agents, impregnation time, and activation temperature. Results indicated a robust adsorption capacity, with the Langmuir isotherm model fitting well to the experimental data. The pseudo-second-order kinetic model demonstrated high applicability, highlighting the potential of the developed adsorbent for wastewater treatment applications. The adsorbent exhibited impressive iodine adsorption capacities ranging from 336.42 to 1250.09mg/g, with efficient removal rates of over 95% for methylene blue and 75% for methyl red dyes within specific time frames.

Synthesis of aluminum alginate/graphene oxide/boehmite biopolymeric nanohybrid for the decontamination of Cu(II) and 2-chlorophenol

BackgroundSustainable biomaterials are crucial in wastewater treatment applications and are constantly in demand. Multifunctional nanohybrids can eliminate organic and inorganic pollutants from wastewater. MethodsHerein, aluminum alginate/graphene oxide/boehmite (Al-Alg/GO/AlOOH) has been synthesized and characterized using Fourier Transform Infrared Spectrophotometer (FT-IR), Transmission Electron Microscopy (TEM), and X-ray diffraction (XRD). The scavenging of 2-chlorophenol (2-CP) and copper (II)) onto synthesized hybrid biopolymer has been investigated as a function of reaction time, influence of pH, initial concentrations, and temperatures. Significant FindingsThe adsorption of Cu(II) onto Al-Alg/GO/AlOOH nanohybrid was more favorable than the 2-CP. The scavenging of Cu(II) and 2-CP was pH dependent and optimum adsorption capacity was found 83 mg/g for Cu(II) at pH 5.5 and 63 mg/g at pH 9.0 for 2-CP, respectively. The Cu(II) and 2-CP adsorption best fit the Redlich-Peterson (R-P) isotherm model. The equilibrium kinetic data for Cu(II) adsorption was fitted well to the Elovich model, and 2-CP adsorption was closely fitted to the pseudo-first-order (PFO) kinetic model. Cu(II) scavenging was spontaneous and endothermic, while, 2-CP adsorption was exothermic. Cu(II) and 2-CP adsorption mechanisms onto Al-Alg/GO/AlOOH have proposed mainly attraction forces, complexation, and hydrogen bonding. After five successive regenerations, Al-Alg/GO/AlOOH was considered a recyclable and promising adsorbent for removing organic and inorganic pollutants from the contaminated aquatic environment.

Photocatalytic activity of barium titanate composites with zinc oxide doped with lanthanide ions for sulfamethoxazole degradation

This comprehensive study delves into the structural and optical characteristics of barium titanate (BT) and zinc oxide (ZnO) heterostructures doped with europium (Eu), erbium (Er), and ytterbium (Yb), alongside their application in the photodegradation of sulfamethoxazole antibiotic (SMX). The heterostructures, prepared via a hydrothermal process, exhibit a heterogeneous connection between doped ZnO nanoparticles and the BT dielectric material with crystalline nature and chemical composition. Moreover, a significant reduction in the bandgap of the doped BT@ZnO:Ln heterostructures compared to undoped counterparts, indicating successful dopant incorporation and the creation of new sub-bands within the bandgap. A minimal adsorption interaction between SMX and the nanomaterials was observed. While BT alone exhibited limited photocatalytic activity, doping with ZnO significantly enhanced performance. Notably, the BT@ZnO:Yb heterostructure exhibited exceptional SMX degradation (99%) within 60 minutes. Incorporation of rare-earth ions (Eu, Er, Yb) not only improved photocatalytic activity but also acted as electron scavengers, mitigating electron-hole recombination. Furthermore, the investigation into the reuse of BT@ZnO:Yb 5%mol showed sustained high efficiency over three cycles. Mechanistic insights into SMX degradation pathways highlight the predominant role of hydroxyl radicals and electron-hole processes. Overall, these findings contribute significantly to the advancement of photocatalytic materials based on composites doped with lanthanide ions for applications in environmental wastewater treatment.

Organic pollutants degradation by a superb MXene-based Z-scheme heterojunction Photocatalyst: Synthesize, delamination process, mechanism and toxicity assessment

In this study, a new CeO2/MXene-TiO2 photocatalyst was created using a simple and economical approach and thoroughly characterized by different techniques, including TEM, XPS, BET, XRD, Raman, and SEM. The focus of this research was to improve the degradation of tetracycline (TC), a commonly used antibiotic with known environmental and health risks. To optimize the degradation process, RSM- CCD method was used to systematically vary key parameters including initial TC concentration, photocatalyst dosage, pH and irradiation time. The trapping experiments were revealed that the hydroxyl (•OH) and superoxide anion (•O2-) radicals played a crucial role in this process. An impressive degradation efficiency of 96.60 % was achieved under optimal conditions, attributed to the Z-scheme electron transfer heterojunction, which enhances the generation and separation of oxidant species. LC-MS analysis was employed to elucidate the photodegradation pathway of TC by identifying the reaction intermediates. This analysis facilitated the proposal of a plausible mechanism for TC degradation. The demonstrated efficacy of the CeO₂/MXene-TiO₂ photocatalyst suggests its potential application in wastewater treatment for the significant degradation of persistent organic contaminants.

Phosphorylated chitin from shrimp shell waste: A robust solution for cadmium remediation

In this work, chitin (CT) was isolated from shrimp shell waste (SSW) and was then phosphorylated using diammonium hydrogen phosphate (DAP) as a phosphorylating agent in the presence of urea. The prepared samples were characterized using Scanning Electron Microscopy (SEM) and EDX-element mapping, Fourier Transform Infrared Spectroscopy (ATR-FTIR), X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA/DTG), conductometric titration, Degree of Substitution (DS) and contact angle measurements. The results of characterization techniques reveal the successful extraction and phosphorylation of chitin. The charge content of the phosphorylated chitin (P-CT) was 1.510 mmol·kg−1, the degree of substitution of phosphorus groups grafted on the CT surface achieved the value of 0.33. The adsorption mechanisms appeared to involve electrostatic attachment, specific adsorption (CdO or hydroxyl binding), and ion exchange. Regarding the adsorption of Cd2+, the effect of the adsorbent mass, initial concentration of Cd2+, contact time, pH, and temperature were studied in batch experiments, and optimum values for each parameter were identified. The experimental results revealed that P-CT enhanced the Cd2+ removal capacity by 17.5 %. The kinetic analyses favored the pseudo-second-order model over the pseudo-first-order model for describing the adsorption process accurately. Langmuir model aptly represented the adsorption isotherms, suggesting unimolecular layer adsorption with a maximum capacity of 62.71 mg·g−1 under optimal conditions of 30 °C, 120 min, pH 8, and a P-CT dose of 3 g·L−1. Regeneration experiments evidenced that P-CT can be used for 6 cycles without significant removal capacity loss. Consequently, P-CT presents an efficient and cost-effective potential biosorbent for Cd2+ removal in wastewater treatment applications.

Ultraviolet technology application in urban water supply and wastewater treatment in China: Issues, challenges and future directions

This study thoroughly explores the application of Ultraviolet (UV) water treatment technology in urban wastewater treatment and water supply in China, highlighting its crucial role in enhancing water quality safety. UV technology, with its environmentally friendly and low-carbon characteristics, is deemed more in line with the demands of sustainable development compared to traditional chemical disinfection methods. The widespread application of UV technology in urban wastewater treatment in China, particularly in the context of urban sewage treatment, is examined. However, to better promote and apply UV technology, there is a need to deepen the understanding of this technology and its application among a broad base of users and design units. The importance of gaining in-depth knowledge about the performance of UV water treatment equipment, the design calculation basis, and operational considerations, as well as the ongoing development of relevant standards, is underscored to ensure that the equipment used in projects complies with engineering design and production requirements. Furthermore, the positive trend of UV technology in the field of advanced oxidation, indicating a promising trajectory for engineering applications, is pointed out. Regarding the prospects of industrial development, a thorough analysis is conducted in the article, emphasizing the necessity for all stakeholders to collaborate and adopt a multi-level approach to promote the sustainable development and application of UV water treatment technology. This collaborative effort is crucial for providing effective safeguards for China's environment, ecology, and human health.