Baharak Sajjadi

• Professor (Assistant) at University of Mississippi

Biochar derived from lignocellulosic biomass has been used as a low-cost adsorbent in wastewater treatment applications. Due to its rich porous structure and good electrical conductivity, biochar can be used as a cost-effective electrode material for capacitive deionization of water. In this work, willow biochar was prepared through carbonization o...

Studies have demonstrated the synergism and complexity of ultrasonic (US) treatment of biochar (BC) in H2O with dissolved CO2. The objective of this study is to elucidate the governing mechanistic steps of this three-phase system by a critical review of possible reactions and an experimental study of variables and kinetics, which include the effect...

The third edition of the Handbook, printed 10 years after publication of the first edition, has arrived. Meanwhile, the Keeling curve has moved from 394 to 419 ppm, and evidences of the devastating climate changes have emerged, such as the complete loss of stability of the natural Atlantic Meridional Overturning Circulation (AMOC) (Boers 2021). We...

Compared to traditional biomass and coal-fired power plants, a process that includes integrated pyrolysis and subsequent gasification is a promising technology to deliver a larger electrical output through the production of high-purity hydrogen with a low carbon footprint. Chemical looping can further enhance the biomass contribution to the global...

Primary particles emitted from fuel combustion mainly involve filterable particulate matter (FPM) and condensable particulate matter (CPM). Particularly, CPM has emerged as a subject for further emission control. This study investigated the effects of the sampling temperature and excess air coefficient (EAC) on the total mass, chemical speciation,...

Generation of hydroxyl radicals (⋅OH) is the basis of advanced oxidation process (AOP). This study investigates the catalytic activity of microporous carbonaceous structure for in-situ generation of ⋅OH radicals. Biochar (BC) was selected as a representative of carbon materials with a graphitic structure. The work aims at assessing the impact of BC...

Magnetization facilitates the separation and reuse of adsorbents, but significantly reduces the adsorption capacity. In this study, a double layer magnetized/functionalized biochar composite was synthesized through a hybrid post-pyrolysis magnetization which sustained and even significantly increased the adsorption capacity of microporous carbonace...

The present study investigates the impact of biomass origin on the properties of biochar and its interaction with different treatment conditions, CO2 adsorption, and regeneration ability. The biochars were synthesized from eight biomasses- herbaceous (miscanthus and switchgrass), agro-industrial (corn stover and sugarcane bagasse) and crop residues...

The present study examined the effect of pyrolysis temperature on the physicochemical properties of biochar, activation process and carbon capture. Two different categories of biochars were synthesized from herbaceous (miscanthus and switchgrass) and agro-industrial (corn stover and sugarcane bagasse) feedstock under four different pyrolysis temper...

The co-adsorption of Hg0 and SO3 on pure and Cu/Mn doped CeO2(110) surface were investigated using the Density Functional Theory (DFT) method. A p (2×2) super-cell periodic slab model with seven atomic layers was constructed to represent the CeO2(110) surface. The results indicated that Hg0 physically adsorbed on the CeO2(110) surface, while Hg0 ch...

Conventional carbon activation requires heating carbon at a temperature greater than 700 °C for over 3 h, consuming 18,600 kcal/kg of activated biochar. In contrast, the ultrasound treatment method is conducted at ambient condition for a very short duration (∼30 s, which requires about 1135 kcal/kg of activated BC produced. The advanced low-tempera...

Biochar has seen an explosion of research over the past decade as an environmentally sustainable material for enhancing agricultural yields, treating wastewater, and sequestering atmospheric carbon. In contrast, there is a lack of research into the social and economic sustainability of biochar. To address this gap, we propose environmental justice...

The present study discusses a novel ultrasound promoted amination technique to functionalize graphene oxide (GO) for CO 2 adsorption. Graphene oxide was synthesized following the modified Hummer's method. The developed functionalization technique integrates the advantages of low-frequency ultrasonic physical activation with the chemical functionali...

Worldwide, there is a continuous need to develop alternative treatment methods to replace conventional processes for textile wastewater. In this regard, Fenton oxidation, with the potential of hydroxyl radical production, is an efficient method. Nevertheless, pH dependence, high chemical consumption and sludge production are a few aspects that limi...

A simplified mathematical model was developed to predict the just suspended speed, NJS in a solid-liquid system by analysing the net impeller power consumption to suspend solid particles. A fully baffled tank with an internal diameter of 400mm equipped with a standard Rushton turbine with a diameter of D=T/3 (133mm) was used in this work. Glass bea...

This study investigates the potential of cow dung, an animal manure, as a binder to enhance the physicochemicalproperties of the base pellet (a mixture of wheat straw and rice husk). In thefirst step, preliminary experimentswere performed to select the best composition of wheat straw and rice husk for the base pellet. The selection wasbased on calo...

The present study discusses a novel biochar activation technique consisting of physical modification using low-frequency ultrasound and chemical functionalization with individual amines and their blended mixtures in presence of two activating agents. Acoustic treatment under ultrasonic irradiation exfoliates the biochar’s graphitic clusters, create...

The objectives of a series of our researches are to determine the feasibility of applying ultrasonic pretreatment prior to biochar gasification. As per the initial results, the heating value (HV) of biochar significantly increased after acoustic treatment in water with dissolved CO 2 (AIChE Journal, 2014;60:1054-1065). Accordingly, emphasis of the...

Biochar (BC) generated from thermal and hydrothermal cracking of biomass is a carbon-rich product with the microporous structure. The graphene-like structure of BC contains different chemical functional groups (e.g. phenolic, carboxylic, carbonylic, etc.), making it a very attractive tool for wastewater treatment, CO 2 capture, toxic gas adsorption...

Biochar is a solid by-product of thermochemical conversion of biomass to bio-oil and syngas. It has a carbonaceous skeleton, a small amount of heteroatom functional groups, mineral matter, and water. Biochar’s unique physicochemical structures lead to many valuable properties of important technological applications, including its sorption capacity....

The main objective of a series of our researches is to develop a novel acoustic-based method for activation of biochar. This study investigates the capability of biochar in adsorbing Ni(II) as a hazardous contaminant and aims at enhancing its adsorption capacity by the addition of extra nitrogen and most probably phosphorous and oxygen containing s...

This paper describes a two-stage biochar activation process for CO2 capture, which includes acoustic treatment and amination. Contrarily to traditional carbon activation at temperatures above 700 °C, both stages of the current process are conducted at or near room temperature. It is known that CO2 can be fixed on the edge carbons of polycyclic arom...

In organic chemistry, Alkenes, also known as olefins, are the unsaturated hydrocarbons with the general formula of CnH2n that contains one or more carbon-carbon double bonds in their chemical structures (RC=CR'). The presence of this double bond allows alkenes to react in ways that alkanes cannot. Hence, alkenes find many diverse applications in in...

We report results of theoretical evaluation of the mechanisms of possible radical reactions on the edge-site of biochar with CO2·-, OḢ, and Ḣ in irradiated aqueous solution. The computational studies were performed for model poly aromatic systems. Obtained mechanisms reflect one of the routes of the oxygen loss accompanied by increase of hydrogen c...

Comparison of UV, H2O2, Fe²⁺, UV/H2O2, UV/Fe²⁺, Fe²⁺/H2O2 and UV/Fe²⁺/H2O2 processes for the removal of percentage color, COD and electrical energy per order from the effluent distillery industry. The results showed that, UV/Fe²⁺/H2O2 process yield higher percentage color and COD removal with low electrical energy per order than UV, UV/H2O2, UV/Fe²...

In this article, the effects of liquid properties and operating conditions on gas-liquid mass transfer under ultrasound irradiation and mechanical stirring were studied and compared. Response Surface Methodology (RSM) was utilized for the design of experiments and evaluation of the influence of operating parameters. The maximum value of volumetric...

In the present work, the efficiency of the sonication, electrocoagulation, and sono-electrocoagulation process for removal of pollutants from the industrial effluent of the pulp and paper industry was compared. The experimental results showed that the sono-electrocoagulation process yielded higher pollutant removal percentage compared to the sonica...

Accurate estimation of transesterification efficiency is needed for designing operational conditions and obtaining the maximum yield of biodiesel production. Accordingly, the objective of this study is to analyse the applicability of three different hybrid soft computing techniques for the prediction of transesterification yield under ultrasound ir...

In this study, the removal of color and COD from landfill leachate, together with the electrical energy per order by the ozonation (O3), sonication (US), O3/H2O2, US/H2O2, O3/Fe²⁺/H2O2, US/Fe²⁺/H2O2 and O3/US/Fe²⁺/H2O2 processes was studied. The experimental results indicated that the color removal, COD removal and electrical energy per order from...

Ultrasound assisted transesterification has recently been introduced as an effective technology for biodiesel synthesis. However, the behaviour of micro bubbles under ultrasound is affected by operating conditions or rheological properties of reaction mixtures. This paper aims at investigating the changes of micro bubbles characteristics when opera...

A hybrid electrocoagulation process using iron electrode was developed for removal of organic pollutants from distillery industrial effluent. Combinations of electrocoagulation process with different advanced oxidation processes such as electrocoagulation, photo–electrocoagulation, peroxi–electrocoagulation and peroxi–photo–electrocoagulation proce...

The use of hybrid Advanced Oxidation Processes (AOPs) for the removal of pollutants from industrial effluents has been extensively studied in recent literature. The aim of this study is to compare the performance of the photo, Fenton, photo-Fenton and ozone-photo-Fenton processes in terms of color removal and chemical oxygen demand (COD) removal of...

This paper aims at investigating the influence of acoustic streaming induced by low-frequency (24kHz) ultrasound irradiation on mass transfer in a two-phase system. The main objective is to discuss the possible mass transfer improvements under ultrasound irradiation. Three analyses were conducted: i) experimental analysis of mass transfer under ult...

The current study aims at analyzing unsteady jet mixing of non-Newtonian fluids and the cavern structure in order to reduce the volume of stagnant zone in anaerobic digester tanks. The study was conducted by integrating computational analysis of the system into the experimental analysis. Accordingly, a highly viscous xanthan gum solution that mimic...

In this study, the effects of ultrasound irradiation on transesterification process and characteristics of the synthesised biodiesel were investigated. The study was divided into two parts. In the first part, Response Surface Methodology and Central Composite Design were employed to design experiments, develop regression model and evaluate individu...

The present study aims to provide a deep insight into the cavitation intensified biodiesel synthesis under ultrasound irradiation. To reach this aim, alkaline transesterification under low-frequency high-power ultrasound irradiation was studied using an ANFIS (Adaptive Neuro-Fuzzy Inference System), which is a robust technique to identify complex i...

The current study aims at introducing a fast and precise method for analyzing the operation of renewable and sustainable energy systems. Accordingly, ultrasound assisted transesterification as a novel method of biodiesel synthesis and biodiesel synthesis using mechanical stirring were selected as the two main systems for renewable energy production...

This study aims at analysing the jet-like acoustic streaming generated under low-frequency and high-power ultrasound irradiation and comparing it with fluid streaming generated by traditional mechanical mixing. The main characteristics of fluid flow, which include radial, axial and tangential terms of velocity and their effects on fluid flow patter...

One of the most pivotal limitations of TiO2 or ZnO based lattices is their photocatalysis activity under visible light irradiation. In this study, a hybrid photocatalyst was generated by doping TiO2/ZnO lattice with copper in order to improve their photo-activity. The main aim was to analyse the sensitivity of photoactivity of Cu-TiO2/ZnO toward op...

This review evaluates computational fluid dynamic applications to analyze solid suspension quality in stirred vessels. Most researchers typically employ either Eulerian-Eulerian or Eulerian-Lagrangian approach to investigate multiphase flow in stirred vessels. With sufficient computational resources, the E-L approach simulates flow structures with...

The influence of sonoluminescence transesterification on biodiesel physicochemical properties was investigated and the results were compared to those of traditional mechanical stirring. This study was conducted to identify the mechanistic features of ultra sonication by coupling statistical analysis of the experiments into the simulation of cavitat...

The 3D simulation of convection and diffusion phenomena within a ceramic membrane during transesterification reaction was the aim of this study. The ceramic membrane was a tubular micro porous TiO2/Al2O3 packed with the heterogeneous catalyst. The Navier–Stokes, Brinkman and Stephan–Maxwell equations were applied for investigation of fluid flow rea...

Among the biofuels currently in use or researched, biodiesel is considered as an ideal alternative for diesel due to their similar properties. Biodiesel offers great advantages in terms of renewability, biodegradability and sustainability. It is also able to decrease the greenhouse gas emissions and other pollutants. It is free of aromatic or sulfu...

Hydrodynamic and mass transfer coefficient in a split-cylinder airlift reactor for four different oil-in-water micro-emulsions containing kerosene, heavy naphtha, light naphtha, and diesel as oil-based with concentrations of 3%, 5%, and 7 % (v/v) were considered. The experimental results showed that with increasing the oil in water ratio, the gas h...

The current work is aimed to simulate the production of high quality Fatty Acid Methyl Esters (biodiesel) production from palm oil in a micro porous ceramic membrane reactor. The TiO2/Al2O3 ceramic membrane was used as the separator and catalytic bed. It was packed with potassium hydroxide catalyst supported on palm shell activated carbon. The inve...

Liquid-liquid flows are common in process industries, particularly in turbulent systems. These systems are usually characterized by the diameter of the dispersed phase and are governed by external forces, deformation, breakup, and coalescence processes. In this review, the common methods and equations used to predict these phenomena will be discuss...

This review aims to establish common approaches and equations used in computational fluid dynamics (CFD) analysis for gas-liquid mixing operations and investigate their strengths and weaknesses. The review concluded that with a sufficient computing strength, Eulerian-Lagrangian approaches can simulate detailed flow structures for dispersed multipha...

A two-dimensional model was used to consider circulation velocity and hold-up in a membrane bioreactor. Membranes were located and simulated (using computational fluid dynamics (CFD)) with three different distances of 5, 7 and 9 mm in an airlift reactor and compared with the results obtained from an airlift reactor without membrane. Gas hold-up in...

The airlift reactor (ALR) is s one of the best two-phase contactor and is it could treat the contaminated air streams through biochemical reactions. Therefore this reactor is used increasingly for applications in biochemical processes and biological waste water treatment processes. In the airlift reactor where purification or treatment of wastewate...

This study is focused on the effect of butanol addition on mass transfer and bubble size dispersion in dilute butanol solutions [from 0 to 1% (v/v)], in a split-cylindrical airlift and compared with pure water. Bubble size distribution is measured by photography and picture analysis. Bubble diameter in dilute butanol solutions is about 3.5 times mo...

In this study, the effect of ethanol addition into pure water and its concentration on bubble diameter, gas hold-up and flow regimes were investigated in an airlift reactor. Air and water with ethanol (concentration ranging from 0%–1%, v/v) were as dispersed and continuous phases, respectively. Superficial gas velocity was considered as an effectiv...

The experimental investigation and its simulation using computational fluid dynamics (CFD) of hydrodynamic and mass transfer for two phase bubbly flow in a split cylindrical airlift reactor were carried out. The turbulence influences on mass transfer and hydrodynamic parameters were considered when packing was installed in the riser zone. Further,...

The influences of aliphatic alcohols (CnH2n+1OH, n = 1–4) and their concentrations (0–1 vol.-%) on gas holdup, liquid circulation velocity, mixing time, and overall volumetric gas-liquid oxygen mass transfer coefficient were considered in a split-cylinder airlift reactor sparged with air. The carbon chain length of the alcohols and their concentrat...

The paper describes the effect of temperature, ammonia concentration and feed flow rate on nitrifying treatment of wastewater usage Computational Fluid Dynamics (CFD) for two phase bubbly flow in a split cylindrical airlift reactor with a 0.085 m initiator diameter and 0.505 m height. Superficial gas velocity was used as the operational parameter,...

The main purpose of this work was to investigate the impacts of operating conditions and liquid properties on the hydrodynamic and mass transfer coefficient in a split-cylindrical airlift bioreactor with oil-in-water micro-emulsions. Four different oil-in-water micro-emulsion systems containing kerosene, heavy naphtha, light naphtha and diesel as o...

Investigation of turbulency on the rate of induced liquid circulation, gas hold-up, mixing time and overall gas–liquid volumetric oxygen mass transfer coefficient. The various types of surfactants (containing Brij58, TritonX-405, Tween40, HCTBr) with various concentrations of 1-5 ppm were examined on the operational characteristics of the reactor....