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 transnational state, neoliberalism and environmental education policy: A New Zealand case study

authors: Tulloch, Lynley

subjects: neoliberalism

abstract: The neoliberalisation of environmental policy (including environmental education) is complex and multifaceted and one in which the transnational state (TNS) is central. In order to address this claim, the first part of this paper explains the transnational state and in particular the role of the UN in redefining sustainable development and environmental education. I show how underpinning this process is the nation states ‘transmission belt’ function in which global policy directives are transmitted to the local level. This is achieved through a discussion of the dissemination of neoliberalised sustainable development policy in New Zealand policy contexts. I demonstrate this process by identifying policy formation located at different points in this process, and then via an analysis of its specific form in the context of EE in New Zealand educational settings. The paper then considers the neoliberal substance of this sustainable development led EE discourse in New Zealand which is linked both with its anthropocentric orientation, and its ‘problem solving’, soft-green managerialist/technological approach to the environment.

text: The transnational state, neoliberalism and environmental education policy: A New Zealand case study The neoliberalisation of environmental policy (including environmental education) is complex and multifaceted and one in which the transnational state (TNS) is central. In order to address this claim, the first part of this paper explains the transnational state and in particular the role of the UN in redefining sustainable development and environmental education. I show how underpinning this process is the nation states ‘transmission belt’ function in which global policy directives are transmitted to the local level. This is achieved through a discussion of the dissemination of neoliberalised sustainable development policy in New Zealand policy contexts. I demonstrate this process by identifying policy formation located at different points in this process, and then via an analysis of its specific form in the context of EE in New Zealand educational settings. The paper then considers the neoliberal substance of this sustainable development led EE discourse in New Zealand which is linked both with its anthropocentric orientation, and its ‘problem solving’, soft-green managerialist/technological approach to the environment.

year: 2016

title: 'Te Kawau Mārō' The Role of Media in Revitalising Te Reo Māori

authors: Hill, Jessie Lee Anahira

subjects: Media

abstract: The intent of this thesis is to investigate the role media plays in relation to the revitalisation of te reo Māori in Aotearoa/New Zealand society. This is essential as the media's latent potential is often underestimated and therefore underutilised. 

For Māori and inevitably te reo Māori, media has been a topic of heated contestation for over a century. It is postulated that throughout this troubled history, media's influence has contributed to an erosion of te reo Māori and then conversely, since the late 20th century, its attempted revival. The journey of te reo Māori from past to present may be likened to a voyage of a traditional 'waka hourua' (voyaging or double hulled canoe). 'Nga ngaru e toru' ('three waves') illustrates the three stages that I have defined as catalysts significantly impacting te reo Māori. 

Grounded firmly in a Kaupapa Māori methodological and theoretical framework based on careful research and intimate cultural knowledge, my innovative approaches to language revitalisation entitled the Tapatoru (triangle) Model 1 and Tapatoru Model 2 will be introduced and explained. These distinct language revitalisation paradigms illustrate the core ingredients needed in effective language revival and illustrate the positioning and function of the media within these strategic models.

text: 'Te Kawau Mārō' The Role of Media in Revitalising Te Reo Māori The intent of this thesis is to investigate the role media plays in relation to the revitalisation of te reo Māori in Aotearoa/New Zealand society. This is essential as the media's latent potential is often underestimated and therefore underutilised. 

For Māori and inevitably te reo Māori, media has been a topic of heated contestation for over a century. It is postulated that throughout this troubled history, media's influence has contributed to an erosion of te reo Māori and then conversely, since the late 20th century, its attempted revival. The journey of te reo Māori from past to present may be likened to a voyage of a traditional 'waka hourua' (voyaging or double hulled canoe). 'Nga ngaru e toru' ('three waves') illustrates the three stages that I have defined as catalysts significantly impacting te reo Māori. 

Grounded firmly in a Kaupapa Māori methodological and theoretical framework based on careful research and intimate cultural knowledge, my innovative approaches to language revitalisation entitled the Tapatoru (triangle) Model 1 and Tapatoru Model 2 will be introduced and explained. These distinct language revitalisation paradigms illustrate the core ingredients needed in effective language revival and illustrate the positioning and function of the media within these strategic models.

year: 2010