Performance of reactivated carbon nanotubes in adsorbing cadmium from aqueous solution

cadmium loaded carbon nanotubes (CNTs) for re-adsorption of the same metal cadmium (Cd). The desorption of cadmium ions (Cd2+) by batch mode laboratory experiments was investigated for hydrochloric and nitric acids, where the former gave better desorption compared to the other acid. Initial experiments revealed that hydrochloric acid (HCl) was better than nitric acid (HNO3)for the desorption of Cd2+ from the CNTs. Optimization study was conducted by design expert software using various molarities of HCl, which resulted in pH of 1.39 (0.1 M), pH 2.43 (0.01 M) and pH 3.53 (0.005 M). Contact time of 20, 50, 80, 110 and 140 minutes were used with fixed agitation of 200 rpm to study the effect of time on the desorption process. Statistical model was developed for the optimum desorption process, which provided a regression model with R2 value of 0.987. The desorbed CNTs were washed with deionized water to remove residual acids and then dried for re-adsorption process. The re-adsorption capacity of cadmium was also determined by batch mode experiments. This study revealed that pH and contact time influenced the desorption and re-adsorption capacity of the CNTs. The optimum condition for desorption was pH 1.39 (0.1 M) hydrochloric acid for 50 minutes agitation. This study also revealed that with this optimum condition, three (3) cycles of desorption process was necessary to remove all cadmium ion from the used CNTs. Re-adsorption capacity of the CNTs, after 3 cycles, was reduced from 8.28 mg/g to 4.23 mg/g. This indicated that about 50% of the adsorption capacity of the CNTs were destroyed or reduced due to the desorption process. Such reduction can also be linked to the destruction of the active sites of the CNT adsorbents

Adsorption of lead from aqueous solution by a novel carbon based adsorbent

Lead (Pb), due to its bioaccumulation ability, has been noted to have detrimental effects on the human body affecting the metabolism, blood and kidneys (Bansal and Goyal, 2005; Bowen, 1996). It is, therefore, imperative that lead be removed from water and wastewater to protect public health and aquatic lives. Multiwall carbon nanotubes (MWCNT) were reported by Li et al. (2003) to have metal sorption capacity of 3–4 times higher than those of powder and granular activated carbon. However, membrane clogging and separation of the nanomaterials from the filtrate pose a challenge. In this work, a novel composite material consisting of carbon nanotubes (CNT) and granular activated carbon (GAC) was synthesised to solve the filtration problem in a static filter. Various percentages of nickel (1%, 3%, 5 and 7%) were used as substrate catalyst during production of the adsorbent and these were linked to the morphology and adsorption capacity of the novel material in lead adsorption. Analyses showed that increased nickel content in the substrate from 1% to 7%, during adsorbent production, resulted in a rough surface of the CNT and increased lead removal from 24% to 89%. Equilibrium concentrations of lead for the adsorbents were achieved at about 60 minutes of contact time. The novel composite material has the potential to remove toxic materials from water and bring benefit to the society

The association between Facebook addiction and depression: a pilot survey study among Bangladeshi students

Social media addiction has become an area of increasing research interest over the past few years. However, there has been no previous research on social media addiction in Bangladesh. The present pilot study is the first ever in Bangladesh to examine the relationship between one specific form of social media addiction (i.e., ‘Facebook addiction’) and its associated predictors. This present study comprised 300 students from the University of Dhaka (Bangladesh) who participated in a survey that included questions relating to socio-demographics, health and behavioral measures, and the Bergen Facebook Addiction Scale (BFAS), and the nine-item Patient Health Questionnaire (PHQ9). The prevalence of FA was 39.7% (cutoff score was ≥18 on the BFAS). Using a regression analysis, the risk of being addicted to Facebook was predicted by being single, having less involvement in physical activities, sleep disturbance (more or less than 6 to 7 h of sleep), time spent on Facebook (≥5 h per day), and depression symptoms. Based on the sample in the present study, the risk of Facebook addiction (as assessed using the BFAS) appears to be a significant issue among Bangladeshi students, and depression to be one of the main comorbid factors

Facebook use and its predictive factors among students: evidence from a lower- and middle-income country, Bangladesh

Background: Facebook is a popular social networking site in the modern world. It has an adverse effect such as impairing daily health and psychological health and also interpersonal relationships when the use becomes problematic. Aims: To examine problematic Facebook use (PFU) and its predictors among Bangladeshi students during the COVID-19 pandemic. Method: A cross-sectional online survey was conducted among 601 Bangladeshi students and collected data related to socio-demographic information, behavioral health, internet use behavior, depression, anxiety and problematic Facebook use [assessed using the Bergen Facebook Addiction Scale (BFAS)]. The data were analyzed using descriptive (frequencies and percentages) and inferential statistics (independent sample t-tests, one-way ANOVAs, correlations, and multivariable linear regression). Results: The results indicated that 29.1% of participants were problematic Facebook users (using cutoff ≥18 out of 30). Medical college students had higher mean score on PFU than other students (p < 0.001). In addition, the mean score of PFU was significantly higher among the students who were in a relationship (p = 0.001), did not engage in physical activity (p < 0.001), used the internet more than 5 h per day (p < 0.001), used social media (p < 0.001), and had depression or anxiety symptoms (p < 0.001). PFU was significantly associated with depression and anxiety among the whole sample. Predictive factors for PFU included relationship status, daily internet use time, gaming, social media use, depression, and anxiety. The model predicted almost 33.2% variance for PFU. Conclusions: Findings suggest interventions should be implemented for students with a special focus on medical students who had higher score of PFU than other types of students

Prevalence and psychiatric risk factors of excessive internet use among northern Bangladeshi job-seeking graduate students: a pilot study

Although internet addiction (IA) has been the subject of research in many countries, it is poorly studied in Bangladesh, and previous studies in the country have not examined potential mental health risk factors in relation to the development of IA. The present pilot study attempted to assess the prevalence and associated risk factors of IA among a convenience sample of recently graduated university students actively looking for a job (N = 284) from July to October 2018 in Rajshahi (a city in Bangladesh). The measures included socio-demographic and behavioral variables, the Internet Addiction Test (IAT), and the Depression, Anxiety, and Stress Scale. Surprisingly, no cases of IA were identified in the sample (i.e., the prevalence rate of IA was 0%) which may have been a consequence of the specific population sampled. A total of 3.9% of the participants (n = 11) were classified as excessive users (≥ 60 in IAT). Using regression analysis, the risk factors for excessive internet use were spending more time online (> 5 h daily) and experiencing psychiatric conditions (i.e., depression, stress). It is hoped the present pilot study will facilitate further study in Bangladesh with a more in-depth focus on the socio-demographic and psychiatric morbidities in excessive and problematic internet use. It is also speculated that job-seeking may be a situational protective risk factor for developing IA

Suicide related to the COVID-19 pandemic in India: a systematic review

Background: The suicide rate has increased during the pandemic in India. Moreover, several studies, especially press-media reporting suicide studies have been conducted but no systematic review has been attempted in this context. Therefore, the present study systematically investigated the risk factors associated with suicidal behaviors, and the method of suicide during the COVID-19 pandemic in India. Methods: Following the PRISMA guidelines, a systematic search was performed to include papers published up until September 30, 2022. From an initial 144 papers, 18 studies which met the inclusion criteria were included in the present review. The Pierson’s method was used for quality assessment of the included studies in the present review. Results: The risk factors associated with suicide comprised: (i) socio-demographic factors (e.g., being aged between 31 and 50 years, male, married, unemployed), (ii) behavior and health-related factors (e.g., unavailability of alcohol and alcohol withdrawal symptoms, poor state of physical health and health issues, family disputes, relationship complexities, and sexual harassment), (iii) COVID-19-related factors (e.g., fear of COVID-19, COVID-19 test results, quarantine or isolation, financial hardship due to the pandemic, having influenza-like symptoms, experiencing stigmatization and ostracism despite testing negative, separation from family due to transport restrictions, misinterpreting other illness symptoms as COVID-19, saving the village from infection, watching COVID-19 videos on social media, online schooling, perceived stigma toward COVID-19, and being suspected of having COVID-19), and (iv) psychopathological stressors (depression, loneliness, stress, TikTok addiction, and poor mental health, suicidal tendencies, helplessness, and worrying). Hanging was the most common method of suicide. In addition, jumping from high buildings, poisoning, drowning, burning, cutting or slitting throat or wrists, self-immolation, medication overdose, electrocution, pesticide, and gun-shot were also used to carry out the suicide. Conclusions: Findings from this research suggest multiple reasons for suicide during the COVID-19 pandemic and knowledge of such factors could aid in developing suicide prevention strategies focusing the most vulnerable cohorts inside and outside India

How has the COVID-19 pandemic impacted internet use behaviors and facilitated problematic internet use? A Bangladeshi study

Background: The COVID-19 pandemic-related “stay-at-home” and confinement orders has led individuals to be more engaged with technology use (e.g., internet use). For a minority of individuals, excessive use can become problematic and addictive. However, the investigation of problematic internet use in the COVID-19 context is only just emerging. Therefore, the present study investigated the changes in internet use behaviors and addiction rates in comparison with prior Bangladeshi studies. Methods: An online cross-sectional study was carried out among a total of 601 Bangladeshi students between October 7 and November 2, 2020. The survey included questions relating to socio-demographic, behavioral health, online use behaviors, and psychopathological variables. Results: A quarter of the participants (26%) reported having low levels of internet addiction, whereas 58.6% were classed as having moderate internet addiction and 13% severe internet addiction. A total of 4% of the sample were classed as being at risk of severe internet dependency (i.e., scoring over ≥ 80 on IAT). Risk factors for internet addiction included smartphone addiction, Facebook addiction, depression, and anxiety. However, the final hierarchical regression model comprising all variables explained a total of 70.6% variance of problematic internet use. Conclusion: Based on the present findings, it is concluded that individuals are at elevated risk of problematic internet use like other psychological impacts that have been reported during the COVID-19 pandemic. Therefore, risk-reducing measures and healthy control use strategies should be implemented for vulnerable individuals