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1.
Environ Res ; 260: 119670, 2024 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-39048063

RESUMO

Despite advancements in wastewater treatment technologies, heavy metal contamination, especially cadmium (Cd), severely threatens human health and ecosystems. The purpose of this work is to compare the removal of Cd (II) ions from aqueous solutions by chemically modified mixed seaweed biosorbent (CMSB) and physically modified mixed seaweed biosorbent (PMSB). BET, SEM, EDAX, FTIR, and XRD techniques characterized the mixed seaweed biosorbents before and after adsorption. They are well-known for their sustainability, affordability, and biodegradability. The BET study revealed that CMSB had a surface area of 19.682 m2/g, while PMSB had a lower surface area of 14.803 m2/g. The optimum adsorption conditions were a temperature of 303 K, pH of 6.0, and biosorbent dosages of 1 g/L for CMSB and 2.5 g/L for PMSB. For CMSB and PMSB, the most efficient contact times were 40 and 80 min, respectively. The Langmuir model was demonstrated to be the best fit for the experimental data when compared to other isotherm models, with a coefficient of determination, or R2, of 0.9713 and a maximum monolayer capacity of 151.2 mg/g and 181.6 mg/g for physical and chemical activated mixed seaweed biomass. There was a significant relationship between the R2 values of chemically modified and physically modified biomass. The findings demonstrate that pseudo-second-order kinetics more accurately represent the adsorption process than pseudo-first-order and Elovich models. Thermodynamic experiments validated the endothermic, spontaneous and favourable characteristics of the removal process. According to the results of the current study, PMSB and CMSB may be used as effective adsorbents to remove Cd (II) from aqueous solutions.


Assuntos
Cádmio , Alga Marinha , Termodinâmica , Poluentes Químicos da Água , Alga Marinha/química , Adsorção , Cádmio/química , Cádmio/análise , Poluentes Químicos da Água/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos
2.
Chemosphere ; 362: 142729, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38971438

RESUMO

17 global Sustainable Development Goals (SDGs) were established through the adoption of the 2030 Agenda for Sustainable Development by all United Nations members. Clean water and sanitation (SDG 6) and industry, innovation, and infrastructure (SDG 9) are the SDGs focus of this work. Of late, various new companies delivering metal-organic frameworks (MOFs) have blossomed and moved the field of adsorption utilizing MOFs to another stage. Inside this unique circumstance, this article aims to catch recent advancements in the field of MOFs and the utilizations of MOFs relate to the expulsion of arising contaminations that present huge difficulties to water quality because of their steadiness and possible damage to environments and human wellbeing. Customary water treatment techniques regularly neglect to eliminate these poisons, requiring the advancement of novel methodologies. This study overviews engineering techniques for controlling MOF characteristics for better flexibility, stability, and surface area. A current report on MOFs gathered new perspectives that are amicably discussed in emergent technologies and extreme applications towards environmental sectors. Various applications in many fields that exploit MOFs are being fostered, including gas storage, fluid separation, adsorbents, catalysis, medication delivery, and sensor utilizations. The surface area of a wide range of MOFs ranges from 103 to 104 m2/g, which exceeds the standard permeability of several material designs. MOFs with extremely durable porosity are more significant in their assortment and variety than other classes of porous materials. The work outlines the difficulties encountered in the synthesis steps and suggests ways to make use of MOFs' value in a variety of contexts. This caters to creating multivariate systems enclosed with numerous functionalities, leading to the synthesis of MOFs that offer a synergistic blend of in-built properties and exclusive applications. Additionally, the MOF-related future development opportunities and challenges are discussed.


Assuntos
Estruturas Metalorgânicas , Poluentes Químicos da Água , Purificação da Água , Estruturas Metalorgânicas/química , Purificação da Água/métodos , Poluentes Químicos da Água/química , Poluentes Químicos da Água/análise , Adsorção , Desenvolvimento Sustentável
3.
Chemosphere ; 355: 141796, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38537711

RESUMO

Polycyclic aromatic hydrocarbons (PAHs) are pervasive ecological pollutants produced essentially during the inadequate burning of organic materials. PAHs are a group of different organic compounds that are made out of various aromatic rings. PAHs pose a serious risk to humans and aquatic ecosystems because of their mutagenic and carcinogenic properties. In this way, there is a critical prerequisite to utilizing successful remediation strategies and methods to limit the dangerous effect of these pollutants on the ecosystem. Biochar has believed of intriguing properties such as simple manufacturing operations and more affordable and more productive materials. Biochar is a sustainable carbonaceous material that has an enormous surface area with bountiful functional groups and pore structure, which has huge potential for the remediation of toxic pollutants. This review emphasizes the occurrence, development, and fate of toxic PAHs in the environment. In the present review, the properties and role of biochar in the removal of PAHs were illustrated, and the influencing factors and an efficient key mechanism of biochar for the remediation of PAHs were discussed in detail. Various surface modification methods can be utilized to improve the biochar properties with the magnetization process; the advancements of modified biochar are pointed out in this review. Finally, the constraints and prospects for the large-scale application of biochar in the remediation of toxic pollutants are highlighted.


Assuntos
Carvão Vegetal , Recuperação e Remediação Ambiental , Hidrocarbonetos Policíclicos Aromáticos , Hidrocarbonetos Policíclicos Aromáticos/química , Carvão Vegetal/química , Recuperação e Remediação Ambiental/métodos , Poluentes Ambientais/química
4.
Environ Toxicol Pharmacol ; 50: 45-57, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28131076

RESUMO

In this research, the microwave assistance has been employed for the preparation of novel material from agro/natural bio-waste i.e. sawdust, for the effective removal of methylene blue (MB) dye from aqueous solution. The characterization of the newly prepared microwave assisted sawdust (MASD) material was performed by using FTIR, SEM and XRD analyses. In order to obtain the maximum removal of MB dye from wastewater, the adsorption experimental parameters such as initial dye concentration, contact time, solution pH and adsorbent dosage were optimized by trial and error approach. The obtained experimental results were applied to the different theoretical models to predict the system behaviour. The optimum conditions for the maximum removal MB dye from aqueous solution for an initial MB dye concentration of 25mg/L was calculated as: adsorbent dose of 3g/L, contact time of 90min, solution pH of 7.0 and at the temperature of 30°C. Freundlich and pseudo-second order models was best obeyed with the studied experimental data. Langmuir maximum monolayer adsorption capacity of MASD for MB dye removal was calculated as 58.14mg of MB dye/g of MASD. Adsorption diffusion model stated that the present adsorption system was controlled by intraparticle diffusion model. The obtained results proposed that, novel MASD was considered to be an effective and low-cost adsorbent material for the removal of dye from wastewater.


Assuntos
Corantes/isolamento & purificação , Azul de Metileno/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Adsorção , Poeira/análise , Monitoramento Ambiental , Micro-Ondas , Águas Residuárias/química , Madeira
5.
J Clin Diagn Res ; 9(4): CC07-10, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26023552

RESUMO

BACKGROUND: Patients of obstructive sleep apnea (OSA) with metabolic syndrome (MetS) are at increased risk of cardiovascular morbidity and mortality. The role of oxidative stress in pathogenesis of OSA and MetS has been widely reported. Continuous positive airway pressure (CPAP) therapy remains the first-line of treatment in OSA. The beneficial effect of long term CPAP therapy in OSA is well-known. However, the effect of short term CPAP on the components of MetS and oxidative stress-antioxidant levels is still unclear. AIM: The present study explored the effects of one night of CPAP therapy on the oxidant-antioxidant status and components of MetS in patients of OSA with MetS. MATERIALS AND METHODS: Twenty adult males and postmenopausal females with MetS and symptoms suggestive of OSA were enrolled in the study. None of the subjects were smoker or alcoholic. They did not consume any drugs that would alter their antioxidant levels. Overnight polysomnography was done to confirm diagnosis and assess CPAP pressure. Following which they spent one night in the sleep lab for CPAP therapy. Blood pressure data and blood samples were collected at baseline and after CPAP. Collected samples were transferred immediately to the laboratory for analysis of serum thiol, lipid peroxidation, insulin resistance (HOMA-IR) and lipid profile. RESULTS: Paired t-test with two-tail significance was used to compare the changes in study parameters in the same patient before and after treatment. The antioxidant level increased and oxidative stress decreased as evidenced by serum thiol concentration (204.2±65.7 vs 254.9±72 µmol/L, p<0.001) and lipid peroxidation levels (13.1±6.2 vs 8.4±3.1 µmol/L, p<0.01).There was a significant decrease in both systolic (132.1±16.1 vs 127.2±14.3 mmHg, p<0.01) and diastolic blood pressure (86.4±9.4 vs 81.2±9.8 mmHg, p<0.01) after one night of CPAP. However, there was no change in lipid parameters and the reduction seen in insulin resistance was not statistically significant. CONCLUSION: One night of CPAP therapy seems to be helpful in reducing oxidative stress, improving antioxidant levels and decreasing the severity of various components of MetS.

6.
J Clin Diagn Res ; 8(10): BC04-7, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25478332

RESUMO

BACKGROUND: The present day life style is changing the circadian rhythm of the body especially in rotating night shift workers. The impact of this prolongs their reaction time. Night shift also interferes with the circadian variation of pupil size which may affect the visual evoked potential. AIM: To compare the visual reaction time, visual evoked potential (VEP) in rotating night shift workers & day workers and also to correlate the changes in visual reaction time with visual evoked potential. MATERIALS AND METHODS: Forty healthy male security guards & staff (25 - 35 y) who did rotating night shifts at least for six months & 40 d workers (25 - 35 y) who did not do night shift in last two years were involved in the study. Visual reaction time and the latency & amplitude of VEP were recorded. RESULT: Kolmogorov- Smirnov test for normalcy showed the latencies & amplitude of VEP to be normally distributed. Student's unpaired t test showed significant difference (p<0.05) in the visual time and in the latencies of VEP between night shift & day workers. There was no significant difference in the amplitude of VEP. CONCLUSION: Night shift workers who are prone to circadian rhythm alteration will have prolonged visual reaction time & visual evoked potential abnormalities. Implementation of Bright Light Therapy would be beneficial to the night shift worker.

7.
J Clin Diagn Res ; 8(7): BC11-3, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25177557

RESUMO

BACKGROUND: Smoking is the single largest preventable cause of disease and premature death and major tobacco related diseases like cancer costs India more than Rs.308.33 billion per year. Cigarette smoking increases the total peripheral blood leukocyte count but its effect on other haematological parameters is largely unexplored.. OBJECTIVE: To study the effect of smoking and its intensity on hematological and lipid parameters. MATERIALS AND METHODS: This cross sectional study included 40 cigarette smokers and 40 non-smokers in the age range of 25 and 40 years at SRM Medical College, Kattangulathur, Tamilnadu, India. In this study the volunteers were otherwise healthy and the smokers were enquired about their intensity of smoking using smoking index. Common hematological and lipid parameters were measured in all subjects. Comparison of smoking status and its intensity among the study subjects were analysed using t-test and ANOVA.. RESULTS: There is a significant increase in levels of haemoglobin, hematocrit, total leukocyte count, total cholesterol, triglycerides, low density lipoprotein (LDL), very low density lipoprotein (VLDL) and reduced levels of high density lipoprotein (HDL) among the smokers. Heavy smokers showed significant dyslipidemia,increase in red blood cell count, total leukocyte count and neutrophil count. CONCLUSION: Increase in hemoglobin, hematocrit, total leucocyte count and dyslipidemia were found significant among smokers and in heavy smokers there is dyslipidemia with increased RBC count, total leukocyte count with specific increase in neutrophils. As per the existing literature, these changes may lead to future fatal cardiac diseases among the smokers.

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