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Fulltext Enhanced Recyclable Magnetized Palm Shell Waste-Based Powdered Activated Carbon for the Removal of Ibuprofen: Insights for Kinetics and Mechanisms

Wong KT, Yoon Y, Jang M

PLoS One, 2015;10(10):e0141013.
PMID: 26496196 DOI: 10.1371/journal.pone.0141013

A novel preparation method of magnetized palm shell waste-based powdered activated carbon (MPPAC, avg. size 112 μm) was developed. The prepared MPPAC was assessed by several physicochemical analyses, and batch tests were performed for ibuprofen (IBP) removal. Field emission scanning electron microscopy (FESEM) and N2 gas isotherms revealed that magnetite and maghemite were homogeneous and deposited mostly on the surface of PPAC without a significant clogging effect on the micropores. Isotherm results showed that 3.8% Fe (w/w) impregnated PPAC [MPPAC-Fe(3.8%)] had about 2.2-fold higher maximum sorption capacity (157.3 mg g-1) and a 2.5-fold higher sorption density (0.23 mg m-2) than pristine PPAC. Both Fourier-transform infrared spectroscopy (FTIR) and isotherm data indicated that the high sorption capacity and density of IBP by MPPAC was primarily attributable to donor-acceptor complexes with the C = O group and dispersive π-π interactions with the carbon surface. Based on kinetic and repeated adsorption tests, pore diffusion was the rate-limiting step, and MPPAC-Fe(3.8%) had about 1.9~2.8- and 9.1~15.8-fold higher rate constants than MPPAC-Fe(8.6%) and palm shell-waste granular activated carbon (PGAC, avg. size 621 μm), respectively. MPPAC showed almost eight fold greater re-adsorption capacity than PPAC due to a thermal catalytic effect of magnetite/maghemite.
Phenyl-functionalized magnetic palm-based powdered activated carbon for the effective removal of selected pharmaceutical and endocrine-disruptive compounds

Wong KT, Yoon Y, Snyder SA, Jang M

Chemosphere, 2016 Jun;152:71-80.
PMID: 26963238 DOI: 10.1016/j.chemosphere.2016.02.090

Triethoxyphenylsilane (TEPS)-functionalized magnetic palm-based powdered activated carbon (MPPAC-TEPS) was prepared and characterized using various spectroscopic methods, and then tested for the removal of bisphenol A, carbamazepine, ibuprofen and clofibric acid. Magnetite film on MPPAC-TEPS was homogeneously coated on the outer surface of palm-based powdered activated carbon (PPAC) through a hydrothermal co-precipitation technique. Followed by silanization of phenyl-functionalized organosilane on MPPAC's magnetic film. As results, micro/mesopore surface area and volume increased without significant pore clogging and iron (Fe) dissolution under the acidic conditions was greatly decreased. The unique structural and chemical features of MPPAC-TEPS were found to be the main reasons for the enhanced adsorption rates and removal capacities of POPs. The presence of electrolytes and different pH values greatly affected the sorption efficiencies. The dominant sorption mechanism of POPs by MPPAC-TEPS was determined to be π-π interaction (physisorption), based on thermodynamic (ΔG°) and differential scanning calorimetry (DSC). Thermal regeneration at a low temperature (350 °C) was an effective method to desorb the retained POPs and enabled to reactivate MPPAC-TEPS with sustained sorption rates and capacities, whereas PPAC was largely exhausted. As a new type of sorbent for POPs, MPPAC-TEPS has operational advantages, such as magnetic separation and stable regeneration.
Removal of lead and bisphenol A using magnesium silicate impregnated palm-shell waste powdered activated carbon: Comparative studies on single and binary pollutant adsorption

Choong CE, Ibrahim S, Yoon Y, Jang M

Ecotoxicol Environ Saf, 2018 Feb;148:142-151.
PMID: 29040822 DOI: 10.1016/j.ecoenv.2017.10.025

In this work, palm shell waste powder activated carbon coated by magnesium silicate (PPAC-MS) were synthesized by the impregnation of magnesium silicate (MgSiO3) using economical material (silicon dioxide powder) via mild hydrothermal approach for the first time. As an effective adsorbent, PPAC-MS simultaneously removes BPA and Pb(II) in single and binary mode. Surprisingly, PPAC-MS exhibited a homogeneous thin plate mesh-like structure, as well as meso- and macropores with a high surface area of 772.1m2g-1. Due to its specific morphological characteristics, PPAC-MS had adsorption capacities of Pb(II) as high as 419.9mgg-1 and 408.8mgg-1 in single mode and binary mode based on Freudliuch isotherm model while those for BPA by PPAC-MS were 168.4mgg-1 and 254.7mgg-1 for single mode and binary modes corresponding to Langmuir isotherm model. Experiment results also indicated that the synergistic removal of BPA occurred because the precipitation process of Pb(II) leads to the co-precipitation of BPA with Pb(OH)2 compound. PPAC-MS showed a good reusability for 5 regeneration cycles using Mg(II) solution followed by thermal treatment. Overall, PPAC-MS has a high potential in the treatment process for wastewater containing both toxic heavy metals and emerging pollutants due to its high sorption capacities and reusability.
Removal of humic and tannic acids by adsorption-coagulation combined systems with activated biochar

Jung C, Phal N, Oh J, Chu KH, Jang M, Yoon Y

J Hazard Mater, 2015 Dec 30;300:808-814.
PMID: 26340547 DOI: 10.1016/j.jhazmat.2015.08.025

Despite recent interest in transforming biomass into bio-oil and syngas, there is inadequate information on the compatibility of byproducts (e.g., biochar) with agriculture and water purification infrastructures. A pyrolysis at 300°C yields efficient production of biochar, and its physicochemical properties can be improved by chemical activation, resulting in a suitable adsorbent for the removal of natural organic matter (NOM), including hydrophobic and hydrophilic substances, such as humic acids (HA) and tannic acids (TA), respectively. In this study, the adsorption affinities of different HA and TA combinations in NOM solutions were evaluated, and higher adsorption affinity of TA onto activated biochar (AB) produced in the laboratory was observed due to its superior chemisorption tendencies and size-exclusion effects compared with that of HA, whereas hydrophobic interactions between adsorbent and adsorbate were deficient. Assessment of the AB role in an adsorption-coagulation hybrid system as nuclei for coagulation in the presence of aluminum sulfate (alum) showed a synergistic effect in a HA-dominated NOM solution. An AB-alum hybrid system with a high proportion of HA in the NOM solution may be applicable as an end-of-pipe solution.
Fulltext Synthesis Mechanism and Thermal Optimization of an Economical Mesoporous Material Using Silica: Implications for the Effective Removal or Delivery of Ibuprofen

Kittappa S, Cui M, Ramalingam M, Ibrahim S, Khim J, Yoon Y, et al.

PLoS One, 2015;10(7):e0130253.
PMID: 26161510 DOI: 10.1371/journal.pone.0130253

Mesoporous silica materials (MSMs) were synthesized economically using silica (SiO2) as a precursor via a modified alkaline fusion method. The MSM prepared at 500°C (MSM-500) had the highest surface area, pore size, and volume, and the results of isotherms and the kinetics of ibuprofen (IBP) removal indicated that MSM-500 had the highest sorption capacity and fastest removal speed vs. SBA-15 and zeolite. Compared with commercial granular activated carbon (GAC), MSM-500 had a ~100 times higher sorption rate at neutral pH. IBP uptake by MSM-500 was thermodynamically favorable at room temperature, which was interpreted as indicating relatively weak bonding because the entropy (∆adsS, -0.07 J mol(-1) K(-1)) was much smaller. Five times recycling tests revealed that MSM-500 had 83-87% recovery efficiencies and slower uptake speeds due to slight deformation of the outer pore structure. In the IBP delivery test, MSM-500 drug loading was 41%, higher than the reported value of SBA-15 (31%). The in vitro release of IBP was faster, almost 100%, reaching equilibrium within a few hours, indicating its effective loading and unloading characteristics. A cost analysis study revealed that the MSM was ~10-70 times cheaper than any other mesoporous silica material for the removal or delivery of IBP.
Fluoride removal by palm shell waste based powdered activated carbon vs. functionalized carbon with magnesium silicate: Implications for their application in water treatment

Choong CE, Wong KT, Jang SB, Nah IW, Choi J, Ibrahim S, et al.

Chemosphere, 2020 Jan;239:124765.
PMID: 31520981 DOI: 10.1016/j.chemosphere.2019.124765

In this study, palm shell activated carbon powder (PSAC) and magnesium silicate (MgSiO3) modified PSAC (MPSAC) were thoroughly investigated for fluoride (F-) adsorption. F- adsorption isotherms showed that PSAC and MPSAC over-performed some other reported F- adsorbents with adsorption capacities of 116 mg g-1 and 150 mg g-1, respectively. Interestingly, the MgSiO3 impregnated layer changed the adsorption behavior of F- from monolayer to heterogeneous multilayer based on the Langmuir and Freundlich isotherm models verified by chi-square test (X2). Thermodynamic parameters indicated that the F- adsorption on PSAC and MPSAC was spontaneous and exothermic. PSAC and MPSAC were characterized using FESEM-EDX, XRD, FTIR and XPS to investigate the F- adsorption mechanism. Based on the regeneration tests using NaOH (0.01 M), PSAC exhibited poor regeneration (<20%) while MPSAC had steady adsorption efficiencies (∼70%) even after 5 regeneration cycles. This is due to highly polarized C-F bond was found on PSAC while Mg-F bond was distinguished on MPSAC, evidently denoting that the F- adsorption is mainly resulted from the exchange of hydroxyl (-OH) group. It was concluded that PSAC would be a potential adsorbent for in-situ F- groundwater remediation due to its capability to retain F- without leaching out in a wide range pH. MPSAC would be an alternative adsorbent for ex-situ F- water remediation because it can easily regenerate with NaOH solution. With the excellent F- adsorption properties, both PSAC and MPSAC offer as promising adsorbents for F- remediation in the aqueous phase.
Fulltext Antituberculosis: synthesis and antimycobacterial activity of novel benzimidazole derivatives

Keng Yoon Y, Ashraf Ali M, Choon TS, Ismail R, Chee Wei A, Suresh Kumar R, et al.

Biomed Res Int, 2013;2013:926309.
PMID: 24381946 DOI: 10.1155/2013/926309

A total of seven novel benzimidazoles were synthesized by a 4-step reaction starting from 4-fluoro-3-nitrobenzoic acid under relatively mild reaction conditions. The synthesized compounds were screened for their antimycobacterial activity against M. tuberculosis H₃₇Rv (MTB-H₃₇Rv) and INH-resistant M. tuberculosis (INHR-MTB) strains using agar dilution method. Three of them displayed good activity with MIC of less than 0.2 μM. Compound ethyl 1-(2-(4-(4-(ethoxycarbonyl)-2-aminophenyl)piperazin-1-yl)ethyl)-2-(4-(5-(4-fluorophenyl)pyridin-3-ylphenyl-1H-benzo[d]imidazole-5-carboxylate (5 g) was found to be the most active with MIC of 0.112 μM against MTB-H₃₇Rv and 6.12 μM against INHR-MTB, respectively.
An efficient and economical treatment for batik textile wastewater containing high levels of silicate and organic pollutants using a sequential process of acidification, magnesium oxide, and palm shell-based activated carbon application

Birgani PM, Ranjbar N, Abdullah RC, Wong KT, Lee G, Ibrahim S, et al.

J Environ Manage, 2016 Dec 15;184(Pt 2):229-239.
PMID: 27717677 DOI: 10.1016/j.jenvman.2016.09.066

Considering the chemical properties of batik effluents, an efficient and economical treatment process was established to treat batik wastewater containing not only high levels of Si and chemical oxygen demand (COD), but also toxic heavy metals. After mixing the effluents obtained from the boiling and soaking steps in the batik process, acidification using concentrated hydrochloric acid (conc. HCl) was conducted to polymerize the silicate under acidic conditions. Consequently, sludge was produced and floated. XRD and FT-IR analyses showed that wax molecules were coordinated by hydrogen bonding with silica (SiO2). The acidification process removed ∼78-95% of COD and ∼45-50% of Si, depending on the pH. In the next stage, magnesium oxide (MgO) was applied to remove heavy metals completely and almost 90% of the Si in the liquid phase. During this step, about 70% of COD was removed in the hydrogel that arose as a consequence of the crosslinking characteristics of the formed nano-composite, such as magnesium silicate or montmorillonite. The hydrogel was composed mainly of waxes with polymeric properties. Then, the remaining Si (∼300 mg/L) in the wastewater combined with the effluents from the rinsing steps was further treated using 50 mg/L MgO. As a final step, palm-shell activated carbon (PSAC) was used to remove the remaining COD to
Sonophotocatalytic degradation of bisphenol A and its intermediates with graphitic carbon nitride

Sunasee S, Leong KH, Wong KT, Lee G, Pichiah S, Nah I, et al.

Environ Sci Pollut Res Int, 2019 Jan;26(2):1082-1093.
PMID: 28290089 DOI: 10.1007/s11356-017-8729-7

Since bisphenol A (BPA) exhibits endocrine disrupting action and high toxicity in aqueous system, there are high demands to remove it completely. In this study, the BPA removal by sonophotocatalysis coupled with nano-structured graphitic carbon nitride (g-C3N4, GCN) was conducted with various batch tests using energy-based advanced oxidation process (AOP) based on ultrasound (US) and visible light (Vis-L). Results of batch tests indicated that GCN-based sonophotocatalysis (Vis-L/US) had higher rate constants than other AOPs and especially two times higher degradation rate than TiO2-based Vis-L/US. This result infers that GCN is effective in the catalytic activity in Vis-L/US since its surface can be activated by Vis-L to transport electrons from valence band (VB) for utilizing holes (h+VB) in the removal of BPA. In addition, US irradiation exfoliated the GCN effectively. The formation of BPA intermediates was investigated in detail by using high-performance liquid chromatography-mass spectrometry (HPLC/MS). The possible degradation pathway of BPA was proposed.
Titanium dioxide-based sonophotocatalytic mineralization of bisphenol A and its intermediates

Sunasee S, Wong KT, Lee G, Pichiah S, Ibrahim S, Park C, et al.

Environ Sci Pollut Res Int, 2017 Jun;24(18):15488-15499.
PMID: 28512708 DOI: 10.1007/s11356-017-9124-0

In this study, bisphenol A (BPA) removal by sonophotocatalysis coupled with commercially available titanium dioxide (TiO2, P25) was assessed in batch tests using energy-based advanced oxidation combining ultrasound (US) and ultraviolet (UV). The kinetics of BPA removal were systematically evaluated by changing operational parameters, such as US frequency and power, mechanical stirring speed, and temperature, but also comparison of single and coupled systems under the optimum US conditions (35 kHz, 50 W, 300 rpm stirring speed, and 20 °C). The combination of US/UV/P25 exhibited the highest BPA removal rate (28.0 × 10-3 min-1). In terms of the synergy index, the synergistic effect of sonophotocatalysis was found to be 2.2. This indicated that sonophotocatalysis has a considerably higher removal efficiency than sonocatalysis or photocatalysis. The removal of BPA was further investigated to identify BPA byproducts and intermediates using high-performance liquid chromatography-mass spectrometry. Five main intermediates were formed during sonophotocatalytic degradation, and complete removal of BPA and its intermediates was obtained after 3 h of operation. The degradation pathway of BPA by sonophotocatalysis was also elucidated.
Fulltext Cardiac Safety and Efficacy of SB3 Trastuzumab Biosimilar for ERBB2-Positive Early Breast Cancer: Secondary Analysis of a Randomized Clinical Trial

Pivot X, Cortés J, Lüftner D, Lyman GH, Curigliano G, Bondarenko IM, et al.

JAMA Netw Open, 2023 Apr 03;6(4):e235822.
PMID: 37022687 DOI: 10.1001/jamanetworkopen.2023.5822

IMPORTANCE: Trastuzumab has been the standard of care for the treatment of patients with ERBB2-positive breast cancer; however, cardiac events have been reported. This long-term follow-up study provides clinical evidence supporting the similarity of a trastuzumab biosimilar (SB3) to reference trastuzumab (TRZ).
OBJECTIVE: To compare cardiac safety and efficacy between SB3 and TRZ for patients with ERBB2-positive early or locally advanced breast cancer after up to 6 years of follow-up.
DESIGN, SETTING, AND PARTICIPANTS: This prespecified secondary analysis of a randomized clinical trial, conducted from April 2016 to January 2021, included patients with ERBB2-positive early or locally advanced breast cancer from a multicenter double-blind, parallel-group, equivalence phase 3 randomized clinical trial of SB3 vs TRZ with concomitant neoadjuvant chemotherapy who completed neoadjuvant and adjuvant treatment.
INTERVENTIONS: In the original trial, patients were randomized to either SB3 or TRZ with concomitant neoadjuvant chemotherapy for 8 cycles (4 cycles of docetaxel followed by 4 cycles of fluorouracil, epirubicin, and cyclophosphamide). After surgery, patients continued SB3 or TRZ monotherapy for 10 cycles of adjuvant treatment per previous treatment allocation. Following neoadjuvant and adjuvant treatment, patients were monitored for up to 5 years.
MAIN OUTCOMES AND MEASURES: The primary outcomes were the incidence of symptomatic congestive heart failure and asymptomatic, significant decrease in left ventricular ejection fraction (LVEF). The secondary outcomes were event-free survival (EFS) and overall survival (OS).
RESULTS: A total of 538 female patients were included (median age, 51 years [range, 22-65 years]). Baseline characteristics were comparable between the SB3 and TRZ groups. Cardiac safety was monitored for 367 patients (SB3, n = 186; TRZ, n = 181). Median follow-up was 68 months (range, 8.5-78.1 months). Asymptomatic, clinically significant LVEF decreases were rarely reported (SB3, 1 patient [0.4%]; TRZ, 2 [0.7%]). No patient experienced symptomatic cardiac failure or death due to a cardiovascular event. Survival was evaluated for the 367 patients in the cardiac safety cohort and an additional 171 patients enrolled after a protocol amendment (538 patients [SB3, n = 267; TRZ, n = 271]). No difference was observed in EFS or OS between treatment groups (EFS: hazard ratio [HR], 0.84; 95% CI, 0.58-1.20; P = .34; OS: HR, 0.61; 95% CI, 0.36-1.05; P = .07). Five-year EFS rates were 79.8% (95% CI, 74.8%-84.9%) in the SB3 group and 75.0% (95% CI, 69.7%-80.3%) in the TRZ group, and OS rates were 92.5% (95% CI, 89.2%-95.7%) in the SB3 group and 85.4% (95% CI, 81.0%-89.7%) in the TRZ group.
CONCLUSIONS AND RELEVANCE: In this secondary analysis of a randomized clinical trial, SB3 demonstrated cardiac safety and survival comparable to those of TRZ after up to 6 years of follow-up in patients with ERBB2-positive early or locally advanced breast cancer.
TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02771795.

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