Kinetics, mechanism, isotherm and thermodynamic studies of liquid phase adsorption of Pb2\mathplus onto wood activated carbon supported zerovalent iron (WAC-ZVI) nanocomposite

The kinetics, mechanism, isotherm, and thermodynamics of adsorption of Pb2+ onto wood-activated carbon-supported zerovalent iron (WAC-nZVI) nanocom- posite was successfully studied. WAC-nZVI was characterized by a combination of spectroscopic and analytical techniques (BET, PZC, FTIR, SEM, and EDX). BET surface area was 101.50 m 2/g and BJH Adsorption average pore diameter 116.73 Å. The adsorption of Pb2+ studied in batch process depends on various operational param- eters ranging from effect of pH to ionic strength. Kinetics data were best described by pseudo-second-order model based on high initial adsorption rate, h2 (166.67 mgg −1 min−1 ) and correlation coefficient (R2 > 0.99). The mechanism was controlled by both external and intraparticle diffusion models confirmed by Bangham and Boyd models. Equilibrium data were fitted to seven isotherm models. The Langmuir monolayer adsorption capacity (77.52 m2 /g) surpassed those previously investi- gated for adsorption of Pb2+ onto nanoadsorbents. Validity of kinetics and isotherm models was studied using three statistical models. Post-adsorption characteriza- tion by SEM, EDX, and FTIR confirmed the presence of Pb2+ on the loaded-WAC-nZVI

Kinetics, mechanism, isotherm and thermodynamic studies of liquid phase adsorption of Pb2+ onto wood activated carbon supported zerovalent iron (WAC-ZVI) nanocomposite

The kinetics, mechanism, isotherm, and thermodynamics of adsorption of Pb2+ onto wood-activated carbon-supported zerovalent iron (WAC-nZVI) nanocomposite was successfully studied. WAC-nZVI was characterized by a combination of spectroscopic and analytical techniques (BET, PZC, FTIR, SEM, and EDX). BET surface area was 101.50 m2/g and BJH Adsorption average pore diameter 116.73 Å. The adsorption of Pb2+ studied in batch process depends on various operational parameters ranging from effect of pH to ionic strength. Kinetics data were best described by pseudo-second-order model based on high initial adsorption rate, h2 (166.67 mgg−1 min−1) and correlation coefficient (R2 > 0.99). The mechanism was controlled by both external and intraparticle diffusion models confirmed by Bangham and Boyd models. Equilibrium data were fitted to seven isotherm models. The Langmuir monolayer adsorption capacity (77.52 m2/g) surpassed those previously investigated for adsorption of Pb2+ onto nanoadsorbents. Validity of kinetics and isotherm models was studied using three statistical models. Post-adsorption characterization by SEM, EDX, and FTIR confirmed the presence of Pb2+ on the loaded-WAC-nZVI. Thermodynamic parameters (∆Ho, ∆So, ∆Go) confirmed the feasibility, spontaneity, and randomness of the adsorption process. This study revealed a great potential of novel WAC-nZVI in effective removal of Pb2+ from waste water

Liquid phase scavenging of Cd (II) and Cu (II) ions onto novel nanoscale zerovalent manganese (nZVMn): Equilibrium, kinetic and thermodynamic studies

Nanostructured zerovalent manganese (nZVMn) was successfully synthesized and characterized by a combination of analytical and spectroscopic techniques. nZVMn was utilized in scavenging of Cd (II) and Cu (II) ions from aqueous solution. The BET surface area of nZVMn was 131.3490 m2/g, adsorption average pore width (170.4736 Å), BJH Adsorption average pore diameter (185.147 Å), and pH(pzc) (5.01). The scavenging process was found to depend on effect of various adsorption physicochemical parameters investigated in batch process. The results revealed a fast kinetics for the adsorption systems; the data fitted well to pseudo second-order and the mechanism was governed by pore diffusion confirmed by Bangham model. The equilibrium data were tested with Langmuir, Freundlich, Temkin, Dubinin-Raduskevuch (D-R), and Halsey Isotherm models. However, equilibrium data were best interpreted by Langmuir and Freundlich isotherm models. Both Kinetic and isotherm models were validated by sum of square error (SSE) and non-linear chi-square (χ2). The Langmuir monolayer maximum adsorption capacities of nZVMn for adsorption of Cd2+ and Cu2+ were 116.28 mg/g and 181.82 mg/g respectively and these superseded several other adsorbents reported. The feasibility, spontaneous and endothermic nature of the adsorption process was unraveled from thermodynamics parameters. Judging from the desorption index and efficiency, effective desorption of loaded nZVMn was achieved using HCl which is further supported chemisorption mechanism. The micrographs of Scanning Electron Microscopy (SEM) before and after adsorption further confirmed the liquid scavenging of the adsorption process. This study unraveled the effective adsorption of Cd2+ and Cu2+ onto novel nZVMn from synthetic industrial wast

Kinetics, mechanism, isotherm and thermodynamic studies of liquid phase adsorption of Pb2+ onto wood activated carbon supported zerovalent iron (WAC-ZVI) nanocomposite

The kinetics, mechanism, isotherm, and thermodynamics of adsorption of Pb2+ onto wood-activated carbon-supported zerovalent iron (WAC-nZVI) nanocomposite was successfully studied. WAC-nZVI was characterized by a combination of spectroscopic and analytical techniques (BET, PZC, FTIR, SEM, and EDX). BET surface area was 101.50 m2/g and BJH Adsorption average pore diameter 116.73 Å. The adsorption of Pb2+ studied in batch process depends on various operational parameters ranging from effect of pH to ionic strength. Kinetics data were best described by pseudo-second-order model based on high initial adsorption rate, h2 (166.67 mgg−1 min−1) and correlation coefficient (R2 > 0.99). The mechanism was controlled by both external and intraparticle diffusion models confirmed by Bangham and Boyd models. Equilibrium data were fitted to seven isotherm models. The Langmuir monolayer adsorption capacity (77.52 m2/g) surpassed those previously investigated for adsorption of Pb2+ onto nanoadsorbents. Validity of kinetics and isotherm models was studied using three statistical models. Post-adsorption characterization by SEM, EDX, and FTIR confirmed the presence of Pb2+ on the loaded-WAC-nZVI. Thermodynamic parameters (∆Ho, ∆So, ∆Go) confirmed the feasibility, spontaneity, and randomness of the adsorption process. This study revealed a great potential of novel WAC-nZVI in effective removal of Pb2+ from waste water

Kinetics, mechanism, isotherm and thermodynamic studies of liquid phase adsorption of Pb²⁺ onto wood activated carbon supported zerovalent iron (WAC-ZVI) nanocomposite

<p>The kinetics, mechanism, isotherm, and thermodynamics of adsorption of Pb²⁺ onto wood-activated carbon-supported zerovalent iron (WAC-nZVI) nanocomposite was successfully studied. WAC-nZVI was characterized by a combination of spectroscopic and analytical techniques (BET, PZC, FTIR, SEM, and EDX). BET surface area was 101.50 m²/g and BJH Adsorption average pore diameter 116.73 Å. The adsorption of Pb²⁺ studied in batch process depends on various operational parameters ranging from effect of pH to ionic strength. Kinetics data were best described by pseudo-second-order model based on high initial adsorption rate, h₂ (166.67 mgg⁻¹ min⁻¹) and correlation coefficient (<i>R</i>² > 0.99). The mechanism was controlled by both external and intraparticle diffusion models confirmed by Bangham and Boyd models. Equilibrium data were fitted to seven isotherm models. The Langmuir monolayer adsorption capacity (77.52 m²/g) surpassed those previously investigated for adsorption of Pb²⁺ onto nanoadsorbents. Validity of kinetics and isotherm models was studied using three statistical models. Post-adsorption characterization by SEM, EDX, and FTIR confirmed the presence of Pb²⁺ on the loaded-WAC-nZVI. Thermodynamic parameters (∆<i>H</i>^o, ∆<i>S</i>^o, ∆<i>G</i>^o) confirmed the feasibility, spontaneity, and randomness of the adsorption process. This study revealed a great potential of novel WAC-nZVI in effective removal of Pb²⁺ from waste water.</p

Two–three parameters isotherm modeling, kinetics with statistical validity, desorption and thermodynamic studies of adsorption of Cu(II) ions onto zerovalent iron nanoparticles

Adsorption of problematic copper ions as one of the endocrine disruptive substances from aqueous solution onto nanoscale zerovalent iron (nZVI) was studied. The high pore size 186.9268 Å, pore diameter 240.753 Å, and BET surface area 20.8643 m2 g−1 and pH(pzc) enlisted nZVI as an efficient nano-adsorbent for treatment of heavy metals from synthetic wastewater. SEM and EDX revealed the morphology and elemental distribution before and after adsorption. 98.31% removal efficiency was achieved at optimum adsorption operational parameters. Of all the thirteen isotherm models, equilibrium data were well fitted to Langmuir. Kinetics and mechanism data across the concentrations from 10 to 200 mg L−1 were analyzed by ten models. PSO best described kinetics data as confirmed by various statistical error validity models. The intraparticle diffusion model described that the intraparticle diffusion was not the only rate-limiting step. The adsorption mechanism was diffusion governed established by Bangham and Boyd models. Feasible, spontaneous, endothermic, and degree of randomness were reveal by the thermodynamic studies. Better desorption index and efficiency were obtained using HCl suggesting multiple mechanism processes. The performance of ZVI suggested it has a great potential for effective removal of endocrine disruptive cationic contaminant from wastewater

Evaluation of the accuracy of the masimo pronto compared to laboratory spectrophotometric method of intraoperative haemoglobin measurement

Background: Transfusion decisions intra-operatively are generally guided by accurate blood loss estimation and intermittent invasive haemoglobin measurement. We investigated the accuracy of non- invasive intraoperative haemoglobin measurement using the Masimo Pronto (SpHb) as compared to laboratory spectrophotometry (tHb). Methods and Materials: This was a cross sectional study of 110 adult patients undergoing surgery with a potential for blood loss of 500 ml and over under general anaesthesia. Haemoglobin level was determined simultaneously postinduction, pre-transfusion and postoperatively using (SpHb) readings from Masimo Pronto® Pulse CO-Oximeter (Rainbow® SET® Technology Masimo Corporation, Irvine, CA) and haemoglobin analyzer with laboratory spectrophotometry (tHb). Results: A total of 244 sample pairs were analysed; 110 postinduction, 24 pre-transfusion and 110 post-operatively. There was a significant difference in mean haemoglobin between SpHb and tHb during the study at all time periods, p&lt;0.0001. The overall mean haemoglobin was SpHb 12.02 ±1.86 g/dl, and tHb10.49 ±1.92 g/dl, p&lt;0.0001, bias (1.5 ±1.76 g/dl), and limits of agreement-1.9 to 5.0 g/dl. There was moderate Pearson correlation (0.57) between SpHb and tHb measurements. The mean pre-transfusion haemoglobin was SpHb 10.25 ±1.96 g/dl, and tHb 8.26 ±1.27 g/dl, p&lt;0.0001, bias, 2.0 ±1.89 g/dl and limits of agreement, -1.7 to 5.7 g/dl. Conclusion: It is concluded that SpHb overestimated haemoglobin measurement as compared with tHb. Hence the Masimo Pronto was found to be inaccurate as compared with laboratory spectrophotometry in intraoperative haemoglobin measurement. The bias was too large and limits of agreement too wide between SpHb and tHb to make appropriate transfusion decisions. Keywords: Haemoglobin, invasive, non-invasive, transfusion, intraoperativ

Sustainable and low-cost Ocimum gratissimum for biosorption of indigo carmine dye: kinetics, isotherm, and thermodynamic studies

In the quest for a sustainable environment and clean water resources, the efficacy of Ocimum gratissimum leave (OGL) for indigo carmine (IC) dye biosorption was studied in a batch technique. The physicochemical properties of OGL supported its suitability for biosorption studies. Of 92.6% removal efficiency was achieved at optimum conditions of pH 2, contact time 120 min, initial IC concentration 500 ppm, temperature 298 K, and 100 mg OGL dose. Kinetic data were best fitted to pseudo second-order (PSO) and the mechanism was pore diffusion governed as validated by sum of square error (SSE) and non-linear chi-square (χ2). Freundlich isotherm model gave the best description at 298 K as supported by Halsey, Redlich–Peterson, and Fowler–Guggenheim confirming the heterogeneous nature of OGL and multilayer biosorption process. Langmuir Qmax (77.52 mg g−1) surpassed those previously reported. SEM and EDX confirmed the reality of the biosorption process. Thermodynamic parameters (ΔH°, ΔS°, ΔG°, and Ea) affirm a feasible, spontaneous, exothermic, and randomness of the process. Results revealed that OGL is a potential and efficient environmentally benign, low cost, and sustainable biosorbents. It is therefore recommended as a bi-functional biosorbent for wastewater treatment

A pilot biomonitoring study of bladder tumor antigen (BTA) in aflatoxin exposed Nigerian villagers

Objective: To correlate the levels of bladder tumour antigen (BTA) with aflatoxin M1 (AFM) in a human population in Nigeria.Subjects and methods: A pilot, observational study was conducted with 22 human subjects randomly recruited from a Nigerian rural community. Serum and first morning urine of participants were analysed for human BTA and AFM1, respectively, using quantitative ELISA assays.Results: All the subjects were positive to AFM1 (mean = 0.235 ± 0.072 ng/mL) while 19 were positive to BTA (mean = 2.340 ± 1.741 ng/mL). A negative relationship occurred between human BTA and AFM level (r = −0.239; P = 0.285). Human BTA (2.86 ± 2.43 ng/mL; P = 0.306) and AFM1 (0.258 ± 0.065 ng/mL; P = 0.643) were higher in subjects 1–20 years. The two biomarkers were not also associated with sexes of the participants (P &gt; 0.05), although they were higher in the female subjects.Conclusion: This study showed that there may not be a connection between aflatoxin exposure and human BTA which is one of the biomarkers of bladder cancer.Keywords: Bladder tumor antigen; Aflatoxin M1; Association; Bladder cancer pathophysiology; Nigeri