title: Characterization and adsorption performance of New Zealand biochar for the removal of paracetamol and ibuprofen from synthetic solutions in batch and column systems

authors: Shein, Shun Lei Shwe Yee

abstract: Pharmaceuticals are a significant class of emerging organic contaminants that have been increasingly detected in aquatic environments. Their persistence and limited removal by conventional treatment methods poses considerable risks to both flora and fauna. The study investigates the adsorption performance of New Zealand-sourced biochar both raw and surface-modified for the removal of two widely used pharmaceuticals, paracetamol and ibuprofen, from aqueous solutions. With its local availability and carbon-rich structure, biochar was evaluated as an innovative solution to address the growing challenge of emerging pharmaceutical pollutants in aquatic environments. The research aimed to characterize the physicochemical properties of biochar and evaluate its adsorption capacity under batch and column configurations, addressing removal efficiency, equilibrium behaviour, kinetic mechanisms, and dynamic breakthrough performance. The biochar was instrumentally analysed by BET surface area analysis, Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM–EDX) to examine the biochar’s surface structure and functional groups. Premium Biochar demonstrated the highest BET surface area (308.3 m²/g), which further increased to 354 m²/g after 30% KOH activation, indicating enhanced porosity and improved availability of adsorption sites. Batch adsorption experiments revealed that paracetamol achieved higher removal efficiencies and adsorption capacities (up to 8.5 mg/g) compared to ibuprofen (maximum of 2.8 mg/g), largely due to its smaller molecular size and greater polarity. The non-linear technique using isotherm and kinetic model was used to validate the process efficiency of pharmaceuticals removal. Kinetic modelling indicated pseudo-second order and Elovich models best described the adsorption mechanisms (R² > 0.997), confirming chemisorption on heterogeneous surfaces as the dominant process. Isotherm analysis showed multilayer Freundlich adsorption for paracetamol and monolayer Langmuir adsorption for ibuprofen reflecting differences in multilayer versus monolayer adsorption behaviour. Column experiments were conducted under single-pass, closed-loop recirculation, and semi-continuous dosing modes. Single-pass continuous flow showed in rapid breakthrough at short empty bed contact times (1.6–4.5 minutes) due to hydraulic limitations. In contrast, closed-loop recirculation columns achieved up to 90% paracetamol removal and 58% ibuprofen removal under extended operation, specifically, the optimal condition when using 1 mm particle size KOH-activated biochar (1 mm KOH-modified biochar, 15 L/min flow, 500 min runtime). Semi-continuous dosing experiments demonstrated gradual adsorbent saturation with final adsorption capacities of approximately 0.43–0.57 mg/g, supporting the need for regeneration strategies in long-term applications.

text: Characterization and adsorption performance of New Zealand biochar for the removal of paracetamol and ibuprofen from synthetic solutions in batch and column systems Pharmaceuticals are a significant class of emerging organic contaminants that have been increasingly detected in aquatic environments. Their persistence and limited removal by conventional treatment methods poses considerable risks to both flora and fauna. The study investigates the adsorption performance of New Zealand-sourced biochar both raw and surface-modified for the removal of two widely used pharmaceuticals, paracetamol and ibuprofen, from aqueous solutions. With its local availability and carbon-rich structure, biochar was evaluated as an innovative solution to address the growing challenge of emerging pharmaceutical pollutants in aquatic environments. The research aimed to characterize the physicochemical properties of biochar and evaluate its adsorption capacity under batch and column configurations, addressing removal efficiency, equilibrium behaviour, kinetic mechanisms, and dynamic breakthrough performance. The biochar was instrumentally analysed by BET surface area analysis, Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM–EDX) to examine the biochar’s surface structure and functional groups. Premium Biochar demonstrated the highest BET surface area (308.3 m²/g), which further increased to 354 m²/g after 30% KOH activation, indicating enhanced porosity and improved availability of adsorption sites. Batch adsorption experiments revealed that paracetamol achieved higher removal efficiencies and adsorption capacities (up to 8.5 mg/g) compared to ibuprofen (maximum of 2.8 mg/g), largely due to its smaller molecular size and greater polarity. The non-linear technique using isotherm and kinetic model was used to validate the process efficiency of pharmaceuticals removal. Kinetic modelling indicated pseudo-second order and Elovich models best described the adsorption mechanisms (R² > 0.997), confirming chemisorption on heterogeneous surfaces as the dominant process. Isotherm analysis showed multilayer Freundlich adsorption for paracetamol and monolayer Langmuir adsorption for ibuprofen reflecting differences in multilayer versus monolayer adsorption behaviour. Column experiments were conducted under single-pass, closed-loop recirculation, and semi-continuous dosing modes. Single-pass continuous flow showed in rapid breakthrough at short empty bed contact times (1.6–4.5 minutes) due to hydraulic limitations. In contrast, closed-loop recirculation columns achieved up to 90% paracetamol removal and 58% ibuprofen removal under extended operation, specifically, the optimal condition when using 1 mm particle size KOH-activated biochar (1 mm KOH-modified biochar, 15 L/min flow, 500 min runtime). Semi-continuous dosing experiments demonstrated gradual adsorbent saturation with final adsorption capacities of approximately 0.43–0.57 mg/g, supporting the need for regeneration strategies in long-term applications.

year: 2025-07-06

title: The LIDS Research Project: usability study report (1/2002)

authors: Thomson, Kirsten

subjects: computer science

abstract: This report represents the University of Waikato Usability Laboratory’s (Usability Laboratory) analysis of the Large Interactive Display Screen (LIDS) technologies as developed by the LIDS Research Group. 
The Usability Laboratory conducted three exploratory-type studies of the LIDS technology over January and February 2002.  The studies each focused on individual elements of the LIDS technology, while at the same time contributing to the general understanding and knowledge of the technology.

text: The LIDS Research Project: usability study report (1/2002) This report represents the University of Waikato Usability Laboratory’s (Usability Laboratory) analysis of the Large Interactive Display Screen (LIDS) technologies as developed by the LIDS Research Group. 
The Usability Laboratory conducted three exploratory-type studies of the LIDS technology over January and February 2002.  The studies each focused on individual elements of the LIDS technology, while at the same time contributing to the general understanding and knowledge of the technology.

year: 2002-07

title: Experiences of New Zealand Māori mothers’ Engagement with health and social services post-COVID-19 2020 lockdown

authors: Barrett, Nikki Maree

subjects: Childbirth

abstract: Background: 
Despite universal provision of maternity care, Māori (Indigenous peoples of Aotearoa/New Zealand) experience significant maternal and infant health disparities compared to their dominant Pākehā (non-Māori) counterparts. This paper examined the lived realities of postnatal Māori māmā (mothers) engaging with health and social services. Enablers and barriers were identified to better understand what is required to strengthen health services’ responsiveness to Māori māmā health needs and aspirations. 

Methods: 
Underpinned by Kaupapa Māori research principles, which are grounded in Māori cultural values, emphasising self-determination, and Māori aspirations, a small cohort of 17 expectant Māori māmā were recruited from a Māori childbirth education programme to participate in a three-phase study. Phase three, the focus of this paper, involved seven semi-structured, open-ended telephone interviews with Māori māmā. A thematic analysis, underpinned by a mana wahine (authority inherent in Māori women) theoretical perspective amplified these experiences. 

Results: 
Five themes were identified that encapsulated participants’ engagement and interactions with health and social services. These themes were as follows: (1) right to enact tino rangatiratanga (autonomy) and self-achievement; (2) responsiveness of services; (3) service and system issues; (4) need for greater choice and opportunity; and (5) impact of COVID-19. 

Conclusions: 
This study privileged the voices of Māori wāhine, highlighting their experiences with a complex and often unresponsive health system. Participants valued services that enabled them to exercise tino rangatiratanga. Echoing the experiences of other Indigenous Peoples, incorporating culturally relevant practices into perinatal health services is crucial for achieving health equity and addressing disparities.

text: Experiences of New Zealand Māori mothers’ Engagement with health and social services post-COVID-19 2020 lockdown Background: 
Despite universal provision of maternity care, Māori (Indigenous peoples of Aotearoa/New Zealand) experience significant maternal and infant health disparities compared to their dominant Pākehā (non-Māori) counterparts. This paper examined the lived realities of postnatal Māori māmā (mothers) engaging with health and social services. Enablers and barriers were identified to better understand what is required to strengthen health services’ responsiveness to Māori māmā health needs and aspirations. 

Methods: 
Underpinned by Kaupapa Māori research principles, which are grounded in Māori cultural values, emphasising self-determination, and Māori aspirations, a small cohort of 17 expectant Māori māmā were recruited from a Māori childbirth education programme to participate in a three-phase study. Phase three, the focus of this paper, involved seven semi-structured, open-ended telephone interviews with Māori māmā. A thematic analysis, underpinned by a mana wahine (authority inherent in Māori women) theoretical perspective amplified these experiences. 

Results: 
Five themes were identified that encapsulated participants’ engagement and interactions with health and social services. These themes were as follows: (1) right to enact tino rangatiratanga (autonomy) and self-achievement; (2) responsiveness of services; (3) service and system issues; (4) need for greater choice and opportunity; and (5) impact of COVID-19. 

Conclusions: 
This study privileged the voices of Māori wāhine, highlighting their experiences with a complex and often unresponsive health system. Participants valued services that enabled them to exercise tino rangatiratanga. Echoing the experiences of other Indigenous Peoples, incorporating culturally relevant practices into perinatal health services is crucial for achieving health equity and addressing disparities.

year: 2025