Publications by authors named "Mark E Zappi"

14 Publications

  • Page 1 of 1

Synergistic adsorption and degradation of sulfamethoxazole from synthetic urine by hickory-sawdust-derived biochar: The critical role of the aromatic structure.

J Hazard Mater 2021 Jun 9;418:126366. Epub 2021 Jun 9.

Department of Civil Engineering, University of Louisiana at Lafayette, Lafayette, LA, 70504, USA; Energy Institute of Louisiana, University of Louisiana at Lafayette, Lafayette, LA, 70504, USA. Electronic address:

This study investigated the adsorptive removal and subsequent degradation of sulfamethoxazole (SMX) from a synthetic urine by biochar (BC). The BCs used in this study were prepared using two different feedstocks with different temperatures. Element analysis and Fourier transform infrared spectroscopy (FTIR) results suggested that the aromaticity of one of the BCs, 700HSBC was significantly different from the 700PSBC although both of them were prepared at the same temperature (700 °C) with similar pore size distributions and specific surface areas. Due to the presence of abundant aromatic structures, 700HSBC showed a higher SMX uptake than 700PSBC, suggesting that the π-π interaction was the main adsorption mechanism. The removal of SMX from the urine was significantly enhanced by adding hydrogen peroxide to the 700HSBC. The carbonate radicals degradation of SMX mechanism was proposed and verified. With 700HSBC having abundant aromatic structures acting as π-electron donors, it could be an efficient activator for peroxymonocarbonate (HCO) to generate carbonate radicals. Hence, it could be concluded that the aromatic structures on BCs play a key role in both of the adsorption and hydrogen peroxide degradation of the SMX resulting in its removal from urine.
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http://dx.doi.org/10.1016/j.jhazmat.2021.126366DOI Listing
June 2021

A comparative study for phosphate adsorption on amorphous FeOOH and goethite (α-FeOOH): An investigation of relationship between the surface chemistry and structure.

Environ Res 2021 08 13;199:111223. Epub 2021 May 13.

Department of Civil Engineering, University of Louisiana at Lafayette, Lafayette, LA, 70504, USA. Electronic address:

Eutrophication is generally caused by excess nitrogen and phosphorus being released into surface waters by runoff. Developing adsorbents for adsorbing phosphate within soil buffer zones and/or water treatment columns may be effective methods to mitigate this problem. In this study, an amorphous FeOOH (AF) and a well-crystallized α-FeOOH (CF) was formulated to compare phosphate adsorption behavior. The physicochemical properties between these species showed significant differences in morphology, crystallization, zeta potential, and specific surface area. The AF exhibited higher phosphate uptake than CF. X-ray photoelectron spectroscopy (XPS) verified that the hydroxyl groups within AF were 13.28% higher than that in CF. The triply coordinated hydroxyl groups (μ-OH) associated with AF and CF appeared at different positions as shown in the diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analyses, confirming that AF contains more adsorption reactive sites (μ-OH). Mechanisms for monodentate formations and a stable six-member ring structure were proposed. The X-ray absorption near the edge structure (XANES) and XPS results suggested that the iron valence in AF was dominated by Fe (III). XANES also demonstrated that the amorphous structure found in the AF was caused by the disordered tetrahedron and octahedron alignments, leading to a higher phosphate adsorption.
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http://dx.doi.org/10.1016/j.envres.2021.111223DOI Listing
August 2021

Uniform Mesoporous Amorphous Cobalt-Inherent Silicon Oxide as a Highly Active Heterogeneous Catalyst in the Activation of Peroxymonosulfate for Rapid Oxidation of 2,4-Dichlorophenol: The Important Role of Inherent Cobalt in the Catalytic Mechanism.

ACS Appl Mater Interfaces 2020 Dec 8;12(51):57190-57206. Epub 2020 Dec 8.

Beijing International Scientific and Technological Cooperation Base of Water Pollution Control Techniques for Antibiotics and Resistance Genes, School of Civil Engineering, Beijing Jiaotong University, 3 Shangyuancun, Beijing 100044, P. R. China.

Amorphous cobalt-inherent silicon oxide (Co-SiOx) was synthesized for the first time and employed as a highly active catalyst in the activation of peroxymonosulfate (PMS) for the rapid oxidation of 2,4-dichlorophenol (2,4-DCP). The characterization results revealed that the 0.15Co-SiOx possessed a high specific surface area of 607.95 m/g with a uniform mesoporous structure (24.33 nm). The X-ray diffraction patterns indicate that the substituted cobalt atoms enlarge the unit cell parameter of the original SiO, and the selected area electron diffraction pattern confirmed the amorphous nature of Co-SiOx. More bulk oxygen vacancies (O) existing in the Co-SiOx were identified to be one of the primary contributors to the significantly enhanced catalytic activation of PMS. The cobalt substitution both creates and stabilizes the surficial O and forms the adequately active Co(II)-O pairs which engine the electron transfer process during the catalytic activities. The active Co(II)-O pairs weaken the average electronegativity of Co/Si and Co/O sites, resulting in the prevalent changes in final state energy, which is the main driving cause of the binding energy shifts in the X-ray photoelectron spectroscopy (XPS) spectra of Si and O among all samples. The increase of the relative proportion of Co(III) in the spent Co-SiOx probably causes the binding energy shifts of the Co XPS spectrum compared to that of the Co-SiOx. The amorphous Co-SiOx outperforms stable and quick 2,4-DCP degradation, achieving a much higher kinetic rate of 0.7139 min at pH = 7.02 than others via sulfate radical advanced oxidation processes (AOPs), photo-Fenton AOPs, HO reagent AOPs, and other AOP approaches. The efficient degradation performance makes the amorphous Co-SiOx as a promising catalyst in removing 2,4-DCP or organic-rich pollutants.
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http://dx.doi.org/10.1021/acsami.0c20341DOI Listing
December 2020

The use of artificial neural network (ANN) for modeling adsorption of sunset yellow onto neodymium modified ordered mesoporous carbon.

Chemosphere 2020 Oct 15;256:127081. Epub 2020 May 15.

Department of Civil Engineering, University of Louisiana at Lafayette, P. O. Box 43598, Lafayette, LA, 70504, USA; Center of Environmental Technology, The Energy Institute of Louisiana, University of Louisiana at Lafayette, P. O. Box 43597, Lafayette, LA, 70504, USA. Electronic address:

Discharging coloring products in water bodies has degraded water quality irreversibly over the past several decades. Order mesoporous carbon (OMC) was modified by embedding neodymium(III) chloride on the surface of OMC to enhance the adsorptive removal towards these contaminants. This paper represents an artificial neural network (ANN) based approach for modeling the adsorption process of sunset yellow onto neodymium modified OMC (OMC-Nd) in batch adsorption experiments. Neodymium modified OMC was characterized using N adsorption-desorption isotherm, TEM micrographs, FT-IR and XPS spectra analysis techniques. 2.5 wt% Nd loaded OMC was selected as the final adsorbent for further experiments because OMC-2.5Nd showed highest removal efficiency of 93%. The ANN model was trained and validated with the adsorption experiments data where initial concentration, reaction time, and adsorbent dosage were selected as the variables for the batch study, whereas the removal efficiency was considered as the output. The ANN model was first developed using a three-layer back propagation network with the optimum structure of 3-6-1. The model employed tangent sigmoid transfer function as input in the hidden layer whereas a linear transfer function was used in the output layer. The comparison between modeled data and experimental data provided high degree of correlation (R = 0.9832) which indicated the applicability of ANN model for describing the adsorption process with reasonable accuracy.
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http://dx.doi.org/10.1016/j.chemosphere.2020.127081DOI Listing
October 2020

Enhanced Pb(II) adsorption onto functionalized ordered mesoporous carbon (OMC) from aqueous solutions: the important role of surface property and adsorption mechanism.

Environ Sci Pollut Res Int 2020 Jul 15;27(19):23616-23630. Epub 2020 Apr 15.

Center for Environmental Technology, The Energy Institute of Louisiana, P. O. Box 43597, Lafayette, LA, 70504, USA.

Functionalized ordered mesoporous carbon (MOMC-NP) was synthesized by chemical modification using HNO and HPO to enhance Pb(II) adsorption. The phosphate functional group represented by P-O-C bonding onto the surface of OMC was verified by FT-IR and XPS. Batch adsorption experiments revealed the improvement of adsorption capacity by 39 times over the virgin OMC. Moreover, the Pb(II) adsorption results provided excellent fits to Langmuir model and pseudo-second-order kinetic model. The adsorption mechanism of Pb(II) onto MOMC-NP revealed the formation of metal complexes with carboxyl, hydroxyl, and phosphate groups through ion exchange reactions and hydrogen bondings. The calculated activation energy was 22.09 kJ/mol, suggesting that Pb(II) adsorption was a chemisorption. At pH>pH, the main Pb(II) existing species of Pb(II) and Pb(OH) combine with the carboxyl, hydroxyl, and phosphate functional groups via electrostatic interactions and hydrogen bonding. All these findings demonstrated that MOMC-NP could be a useful and potential adsorbent for adsorptive removal of Pb(II). Graphical abstract.
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http://dx.doi.org/10.1007/s11356-020-08487-9DOI Listing
July 2020

The effects of carbon disulfide driven functionalization on graphene oxide for enhanced Pb(II) adsorption: Investigation of adsorption mechanism.

Chemosphere 2020 Jun 31;248:126078. Epub 2020 Jan 31.

Department of Chemical Engineering, University of Louisiana at Lafayette, P. O. Box 43675, Lafayette, LA, 70504, USA; Center for Environmental Technology, The Energy Institute of Louisiana, P. O. Box 43597, Lafayette, LA, 70504, USA.

The surface properties of graphene oxide (GO) have been identified as the key effects on the adsorption of Pb(II) from aqueous solutions in this study. This study reveals the effect of the surface reactivity of GO via Carbon Disulfide (CS) functionalization for Pb(II) adsorption. After successfully preparing CS functionalized GO (GOCS), the specific techniques were applied to investigate Pb(II) adsorption onto GOCS. Results indicated that the new sulfur-containing functional groups incorporated onto GOCS significantly enhanced Pb(II) adsorption capacity on GOCS than that of GO, achieving an improvement of 31% in maximum adsorption capacity increasing from 292.8 to 383.4 mg g. The equilibrium adsorption capacity for GOCS was 280.2 mg g having an improvement of 83.2% over that of 152.97 mg g for GO at the same initial concentration of 150 mg L under the optimal pH of 5.7. Moreover, the results of adsorption experiments showed an excellent fit to the Langmuir and Pseudo-Second-Order models indicating the monolayer and chemical adsorption, respectively. The mechanism for Pb(II) adsorption on GOCS was proposed as the coordination, electrostatic interactions, cation-pi interactions, and Lewis acid-base interactions. The regeneration study showed that GOCS had an appreciable reusability for Pb(II) adsorption with the adsorption capacity of 208.92 mg g after five regeneration cycles. In summary, GOCS has been proved to be a novel, useful, and potentially economic adsorbent for the high-efficiency removal of Pb(II) from aqueous solutions.
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http://dx.doi.org/10.1016/j.chemosphere.2020.126078DOI Listing
June 2020

Modeling mass transfer for adsorptive removal of Pb(II) onto phosphate modified ordered mesoporous carbon (OMC).

J Contam Hydrol 2020 Jan 23;228:103562. Epub 2019 Oct 23.

Department of Civil Engineering, University of Louisiana at Lafayette, P. O. Box 43598, Lafayette, LA 70504, USA; Center for Environmental Technology, The Energy Institute of Louisiana, University of Louisiana at Lafayette, P. O. Box 43597, Lafayette, LA 70504, USA. Electronic address:

Phosphate modified ordered mesoporous carbon (MOMC-NP) has been synthesized and proven to be an effective adsorbent for Pb(II) removal from aqueous solutions. However, the key application components of the mass transfer operations and diffusion coefficient have not been determined. In this study, a modified Finite Bath Diffusion Control Model was mathematically developed containing a constant related to the radius of the adsorbent particle and the fractional attainment of adsorption. The adsorption experiments were conducted under various initial Pb(II) concentrations ranging from 60 mg L to 100 mg L. The results suggested that the modified Finite Bath Diffusion Control Model was more applicable to the experimental data than the original Finite Bath Diffusion Control Model. The average value of the diffusion coefficient (λD¯) obtained from the modified finite bath diffusion control model was 1.63 × 10 cm s indicating the effective diffusivity in the adsorption of Pb(II) on MOMC-NP. Overall, the modified Finite Bath Diffusion Control Model exhibited the precise description and simulation of the mass transfer kinetics for Pb(II) adsorption onto MOMC-NP. Therefore, the modified Finite Bath Diffusion Control Model could be effectively used to investigate the mass transfer kinetics of the adsorption process.
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http://dx.doi.org/10.1016/j.jconhyd.2019.103562DOI Listing
January 2020

Nonpoint source pollution.

Water Environ Res 2019 Oct 4;91(10):1114-1128. Epub 2019 Sep 4.

Department of Civil Engineering, University of Louisiana at Lafayette, Lafayette, Louisiana.

A comprehensive review of the research papers published in 2018 focusing on nonpoint source (NPS) pollution is presented in this review article. The identification of pollution from different sources and estimation of NPS pollution using various models are summarized in this review paper. Various innovative techniques are also examined to abate NPS pollution. PRACTITIONER POINTS: The non-point source pollution in 2018 is systematically reviewed and documented. This review evaluates and summarizes the identification, quantification, reduction, and management of NPS pollution. Future perspectives of NPS pollution research are discussed.
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http://dx.doi.org/10.1002/wer.1205DOI Listing
October 2019

Adsorptive removal of resorcinol on a novel ordered mesoporous carbon (OMC) employing COK-19 silica scaffold: Kinetics and equilibrium study.

J Environ Sci (China) 2019 Jan 21;75:307-317. Epub 2018 Apr 21.

Department of Civil Engineering, University of Louisiana at Lafayette, LA 70504, USA; Center for Environmental Technology, The Energy Institute of Louisiana, LA 70504, USA. Electronic address:

Phenolic compounds and their derivatives have been found in industrial wastewater, which pose threats to the natural environment. Ordered mesoporous carbon (OMC) has been identified as an ideal adsorbent possessing high specific surface area and large pore volume to alleviate these pollutants. A novel ordered mesoporous carbon was prepared using COK-19 template with the cubic Fm3m structure for the first time. Ordered mesoporous silica COK-19 was synthesized and reported in 2015. Sucrose as the carbon precursor was impregnated into the mesopores of silica and converted to carbon through carbonization process using sulfuric acid as a catalyst. Ordered mesoporous carbon was obtained after the removal of silica framework using hydrofluoric acid. Boric acid was employed for the preparation of OMCs with tunable pore sizes in the range of 6.9-16.6 nm. Several characterization techniques such as nitrogen adsorption-desorption isotherms, transmission electron microscope (TEM), Fourier transform infrared spectroscopy, Boehm titration and elemental analysis were employed to characterize the OMCs. The pore size analysis and TEM images confirmed that OMC has replicated the mesostructure of the COK-19. Results obtained from adsorption kinetics and isotherms suggest that the Pseudo-second-order model and Langmuir isotherm well described the experimental data.
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http://dx.doi.org/10.1016/j.jes.2018.04.014DOI Listing
January 2019

Nonpoint Source Pollution.

Water Environ Res 2018 Oct;90(10):1872-1898

Department of Civil Engineering, University of Louisiana at Lafayette, Lafayette, LA, 70504, USA.

A review of the literature published during year 2017 on topics relating to nonpoint source pollution (NPS) is presented. This article is written with a view to cater the need of nonpoint source pollution research and to summarize the new advancements in NPS control. Research developments on assessing, monitoring, and controlling the nonpoint source pollution are the main focus of this review. Future research topics related to NPS are also recommended.
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http://dx.doi.org/10.2175/106143017X15131012188033DOI Listing
October 2018

Molecular simulation and experimental validation of resorcinol adsorption on Ordered Mesoporous Carbon (OMC).

J Hazard Mater 2018 Jul 27;354:258-265. Epub 2018 Apr 27.

Department of Civil Engineering, University of Louisiana at Lafayette, P. O. Box 43598, Lafayette, LA, 70504, USA; Center for Environmental Technology, The Energy Institute of Louisiana, P. O. Box 43597, Lafayette, LA, 70504, USA. Electronic address:

Numerous research works have been devoted in the adsorption area using experimental approaches. All these approaches are based on trial and error process and extremely time consuming. Molecular simulation technique is a new tool that can be used to design and predict the performance of an adsorbent. This research proposed a simulation technique that can greatly reduce the time in designing the adsorbent. In this study, a new Rhombic ordered mesoporous carbon (OMC) model is proposed and constructed with various pore sizes and oxygen contents using Materials Visualizer Module to optimize the structure of OMC for resorcinol adsorption. The specific surface area, pore volume, small angle X-ray diffraction pattern, and resorcinol adsorption capacity were calculated by Forcite and Sorption module in Materials Studio Package. The simulation results were validated experimentally through synthesizing OMC with different pore sizes and oxygen contents prepared via hard template method employing SBA-15 silica scaffold. Boric acid was used as the pore expanding reagent to synthesize OMC with different pore sizes (from 4.6 to 11.3 nm) and varying oxygen contents (from 11.9% to 17.8%). Based on the simulation and experimental validation, the optimal pore size was found to be 6 nm for maximum adsorption of resorcinol.
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http://dx.doi.org/10.1016/j.jhazmat.2018.04.072DOI Listing
July 2018

Methanogenesis under acidic pH conditions in a semi-continuous reactor system.

Bioresour Technol 2008 Nov 7;99(17):8075-81. Epub 2008 May 7.

Department of Chemical and Materials Engineering, University of Alabama in Huntsville, 130 Engineering Building, Huntsville, AL 35899, United States.

Operating an anaerobic digester at low pH could offer several advantages over operation at neutral pH. Most wastewater streams targeted for anaerobic digestion are inherently acidic, requiring alkalinity supplementation (at added expense) to buffer the pH at neutral. Additionally, previously published work completed by the authors using batch systems suggested that lowering the system pH could increase methane production by as much as 30%. The goal of this research was to evaluate the feasibility of sustaining methanogenesis at low pH in a semi-continuous laboratory-scale fermentor. Significant methane production was achieved in a system ranging in pH from approximately 4.0-5.3. Results show that, if the consortium is allowed to sufficiently acclimate to acidic conditions, methanogenesis can be maintained under acidic pH conditions, resulting in overall chemical oxygen demand (COD) reduction and methane production comparable to that achieved in a neutral pH system.
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http://dx.doi.org/10.1016/j.biortech.2008.03.068DOI Listing
November 2008

Feasibility of methanogenic digestion applied to a low pH acetic acid solution.

Bioresour Technol 2007 May 22;98(8):1579-85. Epub 2006 Sep 22.

Department of Chemical and Materials Engineering, University of Alabama in Huntsville, 130 Engineering Building, Huntsville, AL 35899, United States.

This paper discusses the methanogenic digestion of a synthetic acetic acid wastewater inoculated using a mixed culture obtained from an anaerobic digester at a municipal wastewater treatment facility. Experiments were conducted in 500mL batch reactors containing an unbuffered acetic acid solution. Test conditions compared methane production and acetic acid degradation at both acidic (pH 4.5) and neutral (pH 7.0) initial system conditions. Results showed that methane production increased by 30% when the initial pH was decreased from 7.0 to 4.5.
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http://dx.doi.org/10.1016/j.biortech.2006.06.019DOI Listing
May 2007

Isopropanol and acetone induces vinyl chloride degradation in Rhodococcus rhodochrous.

J Ind Microbiol Biotechnol 2003 Nov 7;30(11):651-5. Epub 2003 Nov 7.

Department of Biological Sciences, Mississippi State University, PO Box GY, MS 39762, USA.

In situ bioremediation of vinyl chloride (VC)-contaminated waste sites requires a microorganism capable of degrading VC. While propane will induce an oxygenase to accomplish this goal, its use as a primary substrate in bioremediation is complicated by its flammability and low water solubility. This study demonstrates that two degradation products of propane, isoproponal and acetone, can induce the enzymes in Rhodococcus rhodochrous that degrade VC. Additionally, a reasonable number of cells for bioremediation can be grown on conventional solid bacteriological media (nutrient agar, tryptic soy agar, plate count agar) in an average microbiological laboratory and then induced to produce the necessary enzymes by incubation of a resting cell suspension with isopropanol or acetone. Since acetone is more volatile than isopropanol and has other undesirable characteristics, isopropanol is the inducer of choice. It offers a non-toxic, water-soluble, relatively inexpensive alternative to propane for in situ bioremediation of waste sites contaminated with VC.
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http://dx.doi.org/10.1007/s10295-003-0091-8DOI Listing
November 2003
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