Investigating the potential of using solid waste generated from stone cutting factories for phenol removal from wastewater: A study of adsorption kinetics and isotherms

Remarkably toxic, phenol requires efficient elimination from water. This study investigates the utilization of solid waste generated by stone-cutting factories for extracting phenol from wastewater. The solid waste underwent thermal treatment at 105 °C for 3 h for characterization. Batch adsorption experiments systematically assessed parameters like phenol concentration, adsorbent mass, contact time, temperature, and pH. Optimal removal transpired at pH 7.5, reaching equilibrium within 4 h. Phenol uptake equilibrium values were 8.1, 13.3, 16.2, 20.2, and 28.1 mg/g for initial concentrations of 50, 100, 150, 200, and 300 mg/L, respectively using 1 g of adsorbent at ambient temperature. The Langmuir model fit acceptably, yet the Freundlich model surpassed it. The most suitable kinetics model for phenol adsorption was the pseudo-second-order. The nature of the adsorption process was endothermic. Importantly, this study pioneers the promising application of solid waste generated from stone-cutting factories as an adsorbent material for effective phenol removal, offering a sustainable approach. Notably, no previous study has been conducted on phenol removal from wastewater using this specific adsorbent, rendering this work pivotal in exploring its potential. This solid waste presents an economical, readily available, and environmentally benign material for the adsorption process, expected to exhibit substantial adsorption capacity

Processing and characterization of magnetic composites of activated carbon, fly ash, and beach sand as adsorbents for Cr(VI) removal

The objective of this study is to prepare magnetic composites as adsorbents for Cr(VI) from wastewater. The prepared composites are magnetic activated carbon (M-AC), magnetic ash (M-ASH), and magnetic sand (M-SAND). These composites were characterized using XRF, FTIR, XRD, and TGA, and then tested as adsorbents for toxic Cr(VI) ions from synthetic wastewater. The elemental analysis of the composites showed a crucial increment in the Fe content of about 6425%, 3600%, and 93% for M-SAND, M-AC, and M-Ash, respectively. Their FTIR spectrum showed the existence of the Fe–O bond vibration, indicating the presence of Fe3O4 particles as confirmed by the XRD pattern. The pseudo-second-order model best described the adsorption kinetic results and the Redlich-Peterson isotherm model accurately described the equilibrium data of ion adsorption by the three composites at 25 and 40 °C with relatively high values of R2. The composites showed their highest adsorption capacities for Cr(VI) ions at 40 °C with an average adsorption capacity of the composites was about 50 mg/g. These relatively high values demonstrate the adsorption ability of the magnetic composites and present a strategy to use the adsorption process for Cr(VI) ions by these composites as efficient adsorbents

Sustainable vs. Conventional Approach for Olive Oil Wastewater Management: A Review of the State of the Art

The main goal of this review is to collect and analyze the recently published research concerning the conventional and sustainable treatment processes for olive mill wastewater (OMW). In the conventional treatment processes, it is noticed that the main objective is to meet the environmental regulations for remediated wastewater without considering the economical values of its valuable constituents such as polyphenols. These substances have many important environmental values and could be used in many vital applications. Conversely, sustainable treatment processes aim to recover the valuable constituents through different processes and then treat the residual wastewater. Both approaches’ operational and design parameters were analyzed to generalize their advantages and possible applications. A valorization-treatment approach for OMW is expected to make it a sustainable resource for ingredients of high economical value that could lead to a profitable business. In addition, inclusion of a recovery process will detoxify the residual OMW, simplify its management treatment, and allow the possible reuse of the vast amounts of processed water. In a nutshell, the proposed approach led to zero waste with a closed water cycle development

Production and Characterization of Controlled Release Urea Using Biopolymer and Geopolymer as Coating Materials

Synthetic polymers-based controlled release urea (CRU) leaves non-biodegradable coating shells when applied in soil. Several alternative green materials are used to produce CRU, but most of these studies have issues pertaining to nitrogen release longevity, process viability, and the ease of application of the finished product. In this study, we utilized tapioca starch, modified by polyvinyl alcohol and citric acid, as coating material to produce controlled release coated urea granules in a rotary fluidized bed equipment. Response surface methodology is employed for studying the interactive effect of process parameters on urea release characteristics. Statistical analysis indicates that the fluidizing air temperature and spray rate are the most influential among all five process parameters studied. The optimum values of fluidizing air temperature (80 degrees C), spray rate (0.13 mL/s), atomizing pressure (3.98 bar), process time (110 min), and spray temperature (70 degrees C) were evaluated by multi-objective optimization while using genetic algorithms in MATLAB((R)). Urea coated by modified-starch was double coated by a geopolymer to enhance the controlled release characteristics that produced promising results with respect to the longevity of nitrogen release from the final product. This study provides leads for the design of a fluidized bed for the scaled-up production of CRU

Electrocoagulation as a Promising Defluoridation Technology from Water: A Review of State of the Art of Removal Mechanisms and Performance Trends

Fluoride ions present in drinking water are beneficial to human health when at proper concentration levels (0.5–1.5 mg L−1), but an excess intake of fluoride (>1.5 mg L−1) may pose several health problems. In this context, reducing high fluoride concentrations in water is a major worldwide challenge. The World Health Organization has recommended setting a permissible limit of 1.5 mg L−1. The application of electrocoagulation (EC) processes has received widespread and increasing attention as a promising treatment technology and a competitive treatment for fluoride control. EC technology has been favourably applied due to its economic effectiveness, environmental versatility, amenability of automation, and low sludge production. This review provides more detailed information on fluoride removal from water by the EC process, including operating parameters, removal mechanisms, energy consumption, and operating costs. Additionally, it also focuses attention on future trends related to improve defluoridation efficiency

A critical review of state-of-the-art electrocoagulation technique applied to COD-rich industrial wastewaters

Electrocoagulation(EC)isoneoftheemergingtechnologiesingroundwaterandwastewatertreatmentasitcombinesthebenefits of coagulation, sedimentation, flotation, and electrochemical oxidation processes. Extensive research efforts implementing EC technologyhavebeenexecutedoverthelastdecadetotreatchemicaloxygendemand(COD)-richindustrialwastewaterswiththe aim to protect freshwater streams (e.g., rivers, lakes) from pollution. A comprehensive review of the available recent literature utilizingECtotreat wastewater withhighCODlevelsispresented.Inaddition,recommendationsareprovidedforfuturestudies to improve the EC technology and broaden its range of application. This review paper introduces some technologies which are often adopted for industrial wastewater treatment. Then, the EC process is compared with those techniques as a treatment for COD-richwastewater. The EC process is consideredasthe mostprivilegedtechnologybydifferent researchgroupsowingtoits ability to deal with abundant volumes of wastewater. After, the application of EC as a single and combined treatment for CODrichwastewatersisthoroughlyreviewed.Finally,thisreviewattemptstohighlightthepotentialsandlimitationsofEC.Relatedto the EC process in batch operation mode, the best operational conditions are found at 10 V and 60 min of voltage and reaction time, respectively. These last values guarantee high COD removal efficiencies of > 90%. This review also concludes that considerably large operation costs of the EC process appears to be the serious drawback and rendersit asanunfeasibleapproach for handling of COD rich wastewaters. In the end, this review has attempted to highlights the potential and limitation of EC and suggests that vast notably research in the field of continuous flow EC system is essential to introduce this technology as a convincing wastewater technology

A systematic diagnosis of state of the art in the use of electrocoagulation as a sustainable technology for pollutant treatment: An updated review

Electrocoagulation (EC) and electrocoagulation-flotation (ECF) are of widespread interest owing to their effectiveness for the simultaneous abatement of a broad range of pollutants in drinking and waste waters, but their capability can vary significantly depending on the operating conditions. The effect of operating conditions on the performance of EC has been the subject of much debate over the last few decades. This review aims to focus on the application of EC/ECF processes for pollutants removal under different operating conditions, emphasizing the principal issues that compose the foundation of EC/ECF. It has been found that the current density (typically 1–20 mA/cm2), type of electrode (Al or Fe), and electrolysis time are the key process parameters that influence performance. Although some key mechanisms of pollutant abatement in EC/ECF processes have been identified, recent studies have begun to reveal how the underlying removal mechanisms using the EC/ECF processes depend on the nature of pollutant. Key mechanisms of pollutant abatement include charge neutralization, reduction– oxidation, and precipitation/co-precipitation. The development of improved or innovative cell designs, as well as systematic modeling of EC reactors, are needed. Future research focused on hybrid technologies with cost-effective energy supply may lead to innovative treatment options for wastewater treatment

Electrocoagulation as a promising defluoridation technology from water: A review of state of the art of removal mechanisms and performance trends

Fluoride ions present in drinking water are beneficial to human health when at proper concentration levels (0.5-1.5 mg L-1), but an excess intake of fluoride (>1.5 mg L-1) may pose several health problems. In this context, reducing high fluoride concentrations in water is a major worldwide challenge. The World Health Organization has recommended setting a permissible limit of 1.5 mg L-1. The application of electrocoagulation (EC) processes has received widespread and increasing attention as a promising treatment technology and a competitive treatment for fluoride control. EC technology has been favourably applied due to its economic effectiveness, environmental versatility, amenability of automation, and low sludge production. This review provides more detailed information on fluoride removal from water by the EC process, including operating parameters, removal mechanisms, energy consumption, and operating costs. Additionally, it also focuses attention on future trends related to improve defluoridation efficiency. © 2021 by the authors. Licensee MDPI, Basel, Switzerland