title: Kinetic and isotherm studies on adsorption of arsenic using silica based catalytic media

authors: Aremu, James Oyediji

abstract: This study investigates the removal of arsenic (both As (III) and As (V)) from drinking water using a silica based catalytic media (DMI-65). In this study, BET, FTIR, XRD, SEM and XRF were used to characterize the adsorbent before and after contact with As (III) and As (V). Batch experiments were performed to evaluate the adsorption kinetics at different pH (5, 6, 7 and 8.5). The kinetic study showed that a contact time of 6 h was needed to reach equilibrium and the experimental data were best fitted to the pseudo second-order kinetic model for both As (III) and As (V). Several batch tests were conducted with different concentration of arsenic at different pH conditions (5, 6, 7 and 8.5). During the adsorption test, the maximum adsorption of As (III) occurred at pH 5, while As (V) adsorption reached its maximum at pH 8.5. The adsorption data showed a good fit to Langmuir isotherm models and the maximum adsorption capacity of the silica based catalytic media for As (III) and As (V) were estimated to be 0.318 mg/g and 0.237 mg/g respectively.

text: Kinetic and isotherm studies on adsorption of arsenic using silica based catalytic media This study investigates the removal of arsenic (both As (III) and As (V)) from drinking water using a silica based catalytic media (DMI-65). In this study, BET, FTIR, XRD, SEM and XRF were used to characterize the adsorbent before and after contact with As (III) and As (V). Batch experiments were performed to evaluate the adsorption kinetics at different pH (5, 6, 7 and 8.5). The kinetic study showed that a contact time of 6 h was needed to reach equilibrium and the experimental data were best fitted to the pseudo second-order kinetic model for both As (III) and As (V). Several batch tests were conducted with different concentration of arsenic at different pH conditions (5, 6, 7 and 8.5). During the adsorption test, the maximum adsorption of As (III) occurred at pH 5, while As (V) adsorption reached its maximum at pH 8.5. The adsorption data showed a good fit to Langmuir isotherm models and the maximum adsorption capacity of the silica based catalytic media for As (III) and As (V) were estimated to be 0.318 mg/g and 0.237 mg/g respectively.

year: 2019

title: A pulse check on recent developments in time series econometrics

authors: Chan, Felix

abstract: This article motivates and summarizes the contributions of the special issues on Recent Developments in Time Series Econometrics.

text: A pulse check on recent developments in time series econometrics This article motivates and summarizes the contributions of the special issues on Recent Developments in Time Series Econometrics.

year: 2022-12-20

title: Family structure and change in early childhood and the wellbeing of tamariki Maori

authors: Kukutai, Tahu

subjects: family structure

abstract: Internationally there is growing evidence that family structure, and changes in structure, have an impact on children’s health and wellbeing and the intergenerational transmission of inequity. The effects, however, vary by socio-economic context and ethnicity. Using longitudinal data from Growing Up in New Zealand (n = 1349), we examine family structure and change for tamariki Māori during early childhood, and the potential impacts on their development and wellbeing. We find that a stable two-parent family is the primary experience for tamariki Māori, and sole parenthood is transitory. Diverse family trajectories appear to be linked to poorer cognitive and socio-emotional outcomes but are not the main driver. More important are maternal factors, notably age and education, and material hardship. Importantly, higher levels of cultural connectedness among tamariki Māori, which are associated with diverse family forms, seem to promote socio-emotional development. Our study provides further incentive for policy and programmes that centre equity and support access to the determinants of health for tamariki Māori.

text: Family structure and change in early childhood and the wellbeing of tamariki Maori Internationally there is growing evidence that family structure, and changes in structure, have an impact on children’s health and wellbeing and the intergenerational transmission of inequity. The effects, however, vary by socio-economic context and ethnicity. Using longitudinal data from Growing Up in New Zealand (n = 1349), we examine family structure and change for tamariki Māori during early childhood, and the potential impacts on their development and wellbeing. We find that a stable two-parent family is the primary experience for tamariki Māori, and sole parenthood is transitory. Diverse family trajectories appear to be linked to poorer cognitive and socio-emotional outcomes but are not the main driver. More important are maternal factors, notably age and education, and material hardship. Importantly, higher levels of cultural connectedness among tamariki Māori, which are associated with diverse family forms, seem to promote socio-emotional development. Our study provides further incentive for policy and programmes that centre equity and support access to the determinants of health for tamariki Māori.

year: 2020